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[NW_Kohaku]

Hmm... the only other experience I've had with glazes or laquer in a game was with Puzzle Pirates, and I'm pretty sure they used hemp oil in those reactions... but then again, they used hemp derivatives in EVERYTHING but the gunpowder and the rum.

OK, a quick trip to wikipedia so that I can get at least entry-level information on the process says that the best way to translate the process into a working game system would be as follows:

First, we should be able to make unglazed porcelain flasks that can be used to make an alchemist's workshop, like with glass.  Kind of overkill, but maybe there isn't sand?  Actually, since many of these steps will require sand, it may be unavoidable. (I'd like this to be an alternative to glass, or a more expensive, but potentially more profitable industry that could work alongside glass if we make glazing the pottery require sand, then while you can still make unglazed stuff, you lose the potential for it being an alternative, unless we can set up a sand-substitute, like a quartz-bearing stone.)

Next, we need to translate those chemical compositions into resources that are already in DF.  Quartz would be sand (and maybe some other stones, I'm not fluent in geology enough to know), and Feldspar would be things like Microcline, which could be ground down and powdered.  That would form the base of the glaze, needing impurities for its coloration.

Each of these stones should be powderable by crushing in some sort of mechanically-powered crushing machine.  Hopefully, one stone would provide larger stacks of powders, which can themselves produce multiple glazes, so that you don't have to use an entire iron bar to make a single glaze.

Getting iron oxides should be easy enough from all the iron ores or possibly just melting down iron bars (we're working with loose chemical models here, OK?). 

Manganese isn't so openly available, but since Magnetite is a compound of both iron and manganese, you can just straight crush that for both at once.  Pyrolusite is also apparently a manganese source, and is part of DF already, as well. 

Cobalt is well, it's Cobaltite (which is, amusingly, derived from "kobold ore"), but it does say that cobalt is often a byproduct of copper and nickle mining - perhaps the smelting of copper or nickle can produce a small amount of cobalt as a usable waste product?

We already have lead in galena... and it's pretty much useless, too, so yay for making it useful.

Selenium is apparently just a byproduct of making lead, silver, and copper, so I guess just making a combined Pb + Se from crushing galena should work?

Zirconium, aside from all those zircon gems, is apparently found in ilmenite and rutile, and as a side product of tin (and titanium) manufacture.

[Virex]

Typical glaze colours:
Brown: Fe, Mn
Violet / black: Mn
Blue: Co
Red: (Pb + Se)  (poisonous? Are you an elf or what?)
Green: Cu, Cr
White: Zr (white can be created with an especially large array of tricks but this one is easiest)
Yellow: Fe, (Pb+Sb)

"Modeling" colours sounds sensible. That's rather general knowledge and applies to all kinds of glass so if you look at a blue bottle, you know where the blue colour is from.
And if you don't have copper or chrome compounds in your fortress - no green glazes.

There's also the posibility to use gold for redish colours and uranium from pitchblende for greenish and yelowish colours (The romans already did that). Also, ash glazing would be possible using any type of ash, though pearlash would probably give beter results.

[Gazz]

Sn is also another (probably better) option for "white", now that I think about it.
That was just the first that came to mind.

Oh, and the classical salt glaze for stoneware. I mean who cares about the odd bit of HCl...?

Oxidising or reducing firing, crystallisation, craquelée... I didn't want to write a book here. =P

Yes, that list is by no means complete so feel free to add to it - or any other part.
Other options may be more compatible with the available materials in DF.

[darkflagrance]

Perhaps there can be a solution for those concerned that the addition of in-depth porcelain making would detract from developer time that could be used to address other areas of the game.

Simply lay a basic structure for the addition of pottery and porcelain making, and make these mechanics simplistic but moddable

Thus, on one hand not much effort or devotion is required from Toady to get the system into place, and on the other, modders would be able to alter the system with as much detail as they like, in the same way that modders have revamped minerals and reactions to fit their own desired levels of simulation.

A simple way to bring this about would be to tag soil or stone with tokens relating to custom reactions, allow the creation of workshops that require more finely distinguished inputs, and permit the addition of custom substances that are not just metals or stones.

A basic system like this, in which production trees can be added and customized, could also be used to create new processes to manufacture fantasy materials such as, say, soulstones or mithril.

[Virex]

Oh, and the classical salt glaze for stoneware. I mean who cares about the odd bit of HCl...?

Couldn't you just drench the pot to get rid of most of that? Perhaps you'd get sore hands after prolonged use then, but it's not like you're going to notice that if you're storing dried meat in it.

[NW_Kohaku]

Darkflagrance: I don't think this sort of thing is moddable, at least, not with what we have.  We would need a special catagory of materials, new furnace types, a stone grinder, new workshop types, etc.  The parts that would be moddable are the parts that simply add new glazes or add new formula for the composition of the clay body, and there's no real reason why that would be terribly much more work than only putting in a dummy reaction to let players mod in the details.

----

I've been reading up on this with my spare time during work today...

This, a type of salt glazing over clay looks like a good example of how to make upper-middle tier stoneware.  The article basically covers cobalt-glazed stonewares, and mentions lead-glazed stonewares as well. 

I'm looking at the ways that earthenware and stoneware are made, and would like a little more information on the way that clay could be made for them.  Apparently, kaolin is rediculously common, at least in impure forms, from what I'm reading on wikipedia, and regular clay might just be fine for stoneware, while terra cotta might be made from almost any soil?

[darkflagrance]

Darkflagrance: I don't think this sort of thing is moddable, at least, not with what we have.  We would need a special catagory of materials, new furnace types, a stone grinder, new workshop types, etc.  The parts that would be moddable are the parts that simply add new glazes or add new formula for the composition of the clay body, and there's no real reason why that would be terribly much more work than only putting in a dummy reaction to let players mod in the details.

----

I've been reading up on this with my spare time during work today...

This, a type of salt glazing over clay looks like a good example of how to make upper-middle tier stoneware.  The article basically covers cobalt-glazed stonewares, and mentions lead-glazed stonewares as well. 

I'm looking at the ways that earthenware and stoneware are made, and would like a little more information on the way that clay could be made for them.  Apparently, kaolin is rediculously common, at least in impure forms, from what I'm reading on wikipedia, and regular clay might just be fine for stoneware, while terra cotta might be made from almost any soil?

That's exactly the point of my suggestion: allow modders to add new material types (most likely add a material raw and specify uses) and finer requirements for custom workshops. These two additions would basically allow modders to create production processes for entire lines of materials.

Furthermore, by allowing the addition of new types of furniture and containers, with tags allowing what can be contained in them, even more modding possibilities can be realized.

-------

My purpose is to suggest a more general system so that if Toady moves to implement or allow the implementation of this suggestion, he can do it in a general way that vastly expands the possibilities beyond those simply related to porcelain.

[Gazz]

Couldn't you just drench the pot to get rid of most of that? Perhaps you'd get sore hands after prolonged use then, but it's not like you're going to notice that if you're storing dried meat in it.

Drench? HCl is what's going out the chimney.
You don't want to stand downwind from that.

I'm looking at the ways that earthenware and stoneware are made, and would like a little more information on the way that clay could be made for them.  Apparently, kaolin is rediculously common, at least in impure forms, from what I'm reading on wikipedia, and regular clay might just be fine for stoneware, while terra cotta might be made from almost any soil?

Basically, yes.

Pure kaoline is uncommon but kaolinite is part of many clays or intentionally added to get certain properties.

Stoneware has certain demands. You need an Al2O3 rich clay or it doesn't work.
"Good" clays for that are less common and therefore usually more expensive.

Terracotta or common bricks - yes. If it's "loam" there's a good chance it's usable in one way or another. There are exceptions but I don't think the fiddly bits would add any gameplay value.


Medieval style clay body is always mixed and kneaded by hand. Much like in a bakery.
While it's usually "aged" afterwards, that's another unfun item that should be ignored.
Watching your clay lie about and "get better"? I think not.



BTW: I'm a stoneware man (see and see) so I'm somewhat foggy on things like lower temperature glazes, which have a much wider range of available colours.

[NW_Kohaku]

That's exactly the point of my suggestion: allow modders to add new material types (most likely add a material raw and specify uses) and finer requirements for custom workshops. These two additions would basically allow modders to create production processes for entire lines of materials.

Furthermore, by allowing the addition of new types of furniture and containers, with tags allowing what can be contained in them, even more modding possibilities can be realized.

-------

My purpose is to suggest a more general system so that if Toady moves to implement or allow the implementation of this suggestion, he can do it in a general way that vastly expands the possibilities beyond those simply related to porcelain.

Well, if Toady wants to include the ability to mod in hypothetically any kind of industry and the supporting skill sets, the materials, and possibly the ways that dwarves can interact with them, as well as building moddable furniture, then by all means, I hope he goes ahead.

However, considering this is pretty much just something that can be "plugged into" what already exists without much effort, has, as Footkerchief mentioned, been mentioned fairly often, and as such is both at least reasonably desired, as well as probably not going to cause the sorts of bugs that a full raw-ification of that integral a part of the game, I still think this is worth suggesting, and not "wasting Toady's time".  Even if all those things get put into raws, I still hope Toady looks at this, as I think it would be a valuable addition to vanilla DF.

Couldn't you just drench the pot to get rid of most of that? Perhaps you'd get sore hands after prolonged use then, but it's not like you're going to notice that if you're storing dried meat in it.

Drench? HCl is what's going out the chimney.
You don't want to stand downwind from that.

I'm looking at the ways that earthenware and stoneware are made, and would like a little more information on the way that clay could be made for them.  Apparently, kaolin is rediculously common, at least in impure forms, from what I'm reading on wikipedia, and regular clay might just be fine for stoneware, while terra cotta might be made from almost any soil?

Basically, yes.

Pure kaoline is uncommon but kaolinite is part of many clays or intentionally added to get certain properties.

Stoneware has certain demands. You need an Al2O3 rich clay or it doesn't work.
"Good" clays for that are less common and therefore usually more expensive.

Terracotta or common bricks - yes. If it's "loam" there's a good chance it's usable in one way or another. There are exceptions but I don't think the fiddly bits would add any gameplay value.


Medieval style clay body is always mixed and kneaded by hand. Much like in a bakery.
While it's usually "aged" afterwards, that's another unfun item that should be ignored.
Watching your clay lie about and "get better"? I think not.



BTW: I'm a stoneware man (see and see) so I'm somewhat foggy on things like lower temperature glazes, which have a much wider range of available colours.

OK, is there any way to refine kaolinite chemically?  (I'm finding myself, for the first time, wishing my college chemistry course was actually harder.)  What impurities are normally in kaolinite that need to be removed from it to make a more pure kaolin, and would anything like an acid treatment or cooking it with other minerals be able to remove those impurities?  Even if it's a roundabout method, if there's a way to purify common goods into highly valuable goods (the way that trees become ash become potash become pearlash), then it would help put such goods back on the market, without requiring you to only have 5 actual tiles of suitable kaolin, or denying 90% of the players from ever getting a chance to make it, unless they can import some kaolin.

----

I also want to ask what sort of rocks or soil types from inside the game are permissable for glazing?  Sand and clay already seem obvious... I guess we could ask for a tweak that makes rocksalt more common, and make more salt glazing...  But I'd like there to be multiple alternatives that produce less-valuable results than the "ideal" way of crafting pottery, so that anyone can at least get a stab at this stuff.

According to what I'm getting from Wikipedia, you need quartz or something similar for silica, which would be the obvious place for sand, but in sandless maps, it also says you can get quartz from granite (which makes whole friggin' layers, so that's easy to find), as well as sandstone and gniess and quartzite and... well, it's supposed to be the second most common mineral around, just after feldspar... which is microcline and orthoclase.

----

So far, my idea of a ceramics industry goes like this:

Earthenware / Terra Cotta is producable from normal kilns and magma kilns.  Magma kilns can produce these products with no fuel, as they "only" need to be cooked at 900-1100 degrees celcius.  Such kilns can also be used for second-fire glazing, since most of these don't require more than 1100 degree celcius fires, either.  This tier of goods could produce bricks and shingles from common soil types.  This could actually be fairly useful on aquifer levels, or useful for humans who don't have stone.  Pottery made from earthenware levels can be used as a special type of barrel (Jugs or some such special name), however, only if glazed in some way.  The easiest type of glazing would be that ash glazing style, which would simply require throwing some wood or ashes in the kiln with the pot, possibly with some additional material that actually makes the glaze (sand? salt? feldspar powder?).  These jugs could make a good replacement for barrels, although they may, perhaps, need to be "stacks" of jugs to hold the same volume a barrel would hold.  It would be better, however, if ash (or wood) was modded so that we could get several glazings worth of ash per tree, or it still winds up using a tree to make one barrel-replacement (unless you used a metal powder in the glazing).  Such glazes can take place with the original firing.  Earthenware would be cheap (material value 1), and generally good for making practice crafts for your rising potters, as well as making bricks, or other basic materials.  They could potentially make most crafts you can make with stone out of terra cotta, including coffins or statues.  Even better, masonry made of earthenware might hopefully be engravable and paintable, like with many of the extremely decorated facades of real-life temples.

Stoneware could then be the serious industrial ceramics material - taking several coal units (3 or 5?) to fire the high-temperature kiln (1200-1400 degrees celcius), and requiring the air pump to be mechanically powered, as well as a mechanically powered stone crusher to make the powders.  Stonewares would be highly valuable trade goods, beyond the price of clear glass, certainly, and nearing that of pricy metals (something like 10 or 15 material value?).  Stoneware could have those ash glazes, or more expensive decoration-style glazes, which could use multple glaze powders to boost the decoration value, and even be used to paint detailed scenes with multiple colors, creating a skyrocketing final value.  Stoneware could actually be split a little into a lower-grade and higher-grade depending on if you really work the right materials into the clay.  (5 material value versus 15?)

Actual porcelain would be a highest-tier, require large amounts of fuel (5?) for the fires (1350 celcius), very picky material requirements, and yet be very valuable for the effort (material value 40?).  With a legendary craftsdwarf and 6 or so colors, you might potentially make something in artifact-level (or even mid-sized dwarven syrup roast) values.  This process would require powdered kaolin, powdered feldspar (like orthoclase or microcline), and a source of quartz/silica (powdered granite, sandstone, shale, gniess, quartzite, or just plain sand) for the main body. 

Now, the glazing apparently requires silica to make glass, a flux material, and whatever it is you are using as the actual coloring pigment.  Silica is, again, readily available in sand, or by powdering granite, sandstone, or a host of other common stones.  This flux material can be anything with high calcium content, like what we currently use for flux in iron production (I.E. chalk or limestone), something with potassium content (potash), or high sodium content (not so sure about this... it would be nice to get sea salt from evaporating saltwater, but rocksalt is obvious, although maybe other stones could work for this as well?).  Perhaps the best way of handling this would be to just treat any stone that COULD be used for the glaze as interchangable, just for simplicity's sake.  (Hence, you only need one of potash, flux stones, or rock salt, plus one of sand or sandstone or granite or the other quartz-bearing stones' powder, and maybe could designate which to use.)  You then need to add those glaze powders, made out of crushed metal ores, as Gazz and I discussed in a couple of those posts a couple posts up there.

----

On a total side note, all this has made we want to look into making lacquer.  I'm already thinking of making some "Lacquer Shrooms" instead of lacquer trees... although if they were trees or shrubs, then it would potentially give elves somehting they could produce that would actually be valuable, besides caged giant eagles.  I'd like to think that the races in this game have something that is a "specialty", instead of just being exactly like real-life medieval civilizations, but with various bits of technology blacked-out.

[Grendus]

Personally, I'm with DarkFlagrance. Rather than seeing Toady hardcode any of this, I'd like to see the modding functionality added so that players can add industries with this exact depth.

A lot of this is actually probably doable next version. Custom workshops could be made to produce glazes out of specific stones (just add reactions for all the different types of stone or metal that can produce glazes) and entire production lines could be modded in with multiple workshops and everything. The only part that I don't think will be doable is gathering clay, since I think sand is still the only zone gatherable material in the game.

A lot of the in-depth stuff doesn't need to be added. DF doesn't simulate the extremely finicky things like the differences between charcoal and coke produced steel (heck, it completely ignores the carbon being required to bind impurities in ore smelting). Most players would understand that "Loam" or "Clay" would be used for producing "Stoneware", much more complicated than that would be frustrating and could honestly be written off as something "the dwarves handle".

[NW_Kohaku]

Personally, I'm with DarkFlagrance. Rather than seeing Toady hardcode any of this, I'd like to see the modding functionality added so that players can add industries with this exact depth.

A lot of this is actually probably doable next version. Custom workshops could be made to produce glazes out of specific stones (just add reactions for all the different types of stone or metal that can produce glazes) and entire production lines could be modded in with multiple workshops and everything. The only part that I don't think will be doable is gathering clay, since I think sand is still the only zone gatherable material in the game.

A lot of the in-depth stuff doesn't need to be added. DF doesn't simulate the extremely finicky things like the differences between charcoal and coke produced steel (heck, it completely ignores the carbon being required to bind impurities in ore smelting). Most players would understand that "Loam" or "Clay" would be used for producing "Stoneware", much more complicated than that would be frustrating and could honestly be written off as something "the dwarves handle".

I think you misunderstand what my aims are, here.  As I said in my last post, I'm largely interested in just making a list of potential substitutes, if with a number of ingrediants.

When I'm asking if ground granite can be used as a substitute for sand or other quartz/silica materias, that's making things less finicky, in the same way that charcoal and coke are substitutes for one another.

I am interested in real-life pottery, but only for the purposes of making a reasonable facsimilie of the process to be modelled for the game, not to force people to worry about trying to use chemistry to find the proper pH balance of things (although that actually got positive responses in the farming thread when Silverionmox suggested it...).

[3]

mod in hypothetically any kind of industry and the supporting skill sets

We're going that way already. Moddable workshops via the reactions system (which a suggestion like this would essentially come down to something along the lines thereof) + moddable entity positions and occupations/jobs == hypothetically any kind of industry, just with more or less detail depending on the actual process involved. Which appears to be the point of this discussion.

the materials

...I don't see what has to change here.

and possibly the ways that dwarves can interact with them

Maybe, maybe not. I'll talk a little more about this at the prior-to-lattermost point.

as well as building moddable furniture

Inevitable. Probably not too far off, actually, as bloats go.

considering this is pretty much just something that can be "plugged into" what already exists without much effort

...which is almost the point of converting to raw files in the first place; they work within the existing boundaries and don't need special rules just for themselves.

as well as probably not going to cause the sorts of bugs that a full raw-ification of that integral a part of the game

This is a core part of DF's development scheme. Ideally almost everything bar changes to the engine itself will be converted to raws. The entire point of moving away from the sort of content that was in 2D - basically a load of scripted events occuring for absolutely no reason other than them being hardcoded - was so that things could be procedurally generated without any user interaction. Say, in the next version each worldgen gets its own procedurally modified raws - in one world folder all the elves could mine fortresses in the mountains, all the humans could live in dark fortresses, etc..

By taking a general approach, you can have individual societies build up individual techniques. There's no reason to put down a set of hard rules which say "this is the exact way all crafts made in high-temperature kilns are made - there's a very strict procedure to be followed here, and no, you can't deviate". Think about the evolution of a craft like this. You'd have that in motion. Each society at its own stage.

Also, what bugs? I bet you'd get exactly the same bugs either way.

I still think this is worth suggesting, and not "wasting Toady's time".  Even if all those things get put into raws, I still hope Toady looks at this, as I think it would be a valuable addition to vanilla DF.

Exactly how was he suggesting that this was a waste of Toady's time? He was suggesting a more efficient way of approaching the implementation, not telling you to blow it all to hell.

[Gazz]

OK, is there any way to refine kaolinite chemically?  (I'm finding myself, for the first time, wishing my college chemistry course was actually harder.)

Hehehe.

Chemical refining of any bulk materials like pottery raw materials is not feasible.

Worst case, kaolinite - or any sort of clay - can usually be washed out of unwanted materials because of the interaction of clay minerals with water.
The clay would sort of... float... and would be drained while the rest sinks to the bottom.
This is a very energy and water intensive (drying the sludge...) process and avoided if at all possible.

Removing chemical impurities - won't happen.
In a modern lab you may be able to pull off that trick for a few grams of clay but you'll be using some really nasty chemicals. Like... the kind that can dissolve gold.
Solving silicates is a real bitch.

And you cannot "make" kaolinite. It's a pretty tricky mineral structure. Maybe you could grow small bits with an effort comparable to producing pure silicon wafers for microchip production...

  What impurities are normally in kaolinite that need to be removed from it to make a more pure kaolin, and would anything like an acid treatment or cooking it with other minerals be able to remove those impurities?

Remove excessive quartz or any remaining feldspar with water.
Wet processing is very uncommon, except with porcelain.

I also want to ask what sort of rocks or soil types from inside the game are permissable for glazing?  Sand and clay already seem obvious... I guess we could ask for a tweak that makes rocksalt more common, and make more salt glazing...  But I'd like there to be multiple alternatives that produce less-valuable results than the "ideal" way of crafting pottery, so that anyone can at least get a stab at this stuff.

Usually you only use sand (different kinds of) and maybe around 10% of clay.

Funny how there is a boatload of different "rocks" but only 3 or so types of sand.
For every rock there is also a sand. =)

For glazes you'd use quartz and feldspar sand. Usually you get both at once.
That you only need "sand" to create glass in DF isn't that far from the truth.
You're just lucky to get a meltable mix every single time. =)

The melting point is defined by the recipe and which kind (Na, Ca, K) of Feldspar you use.

For Porcelain you'll mostly want potash(orthoclase), for earthenware albite (Na).
Calcite is somewhere in the middle. For stoneware you'll use a mix of K and (Na/Ca).
And no feldspar is ever pure. You always get a mix of several ones.

According to what I'm getting from Wikipedia, you need quartz or something similar for silica, which would be the obvious place for sand, but in sandless maps, it also says you can get quartz from granite (which makes whole friggin' layers, so that's easy to find), as well as sandstone and gniess and quartzite

Getting quartz from granite in any useful fashion isn't gunna work.

Sandstone and gneiss are nothing in particular. That just means that stuff has been metamoprhed into a more or less rocklike cohesion.
Sure, quartz and feldspar are common in either simply because they are common everywhere. You just can't get them out of there unless you're lucky enough to find something like a mostly pure feldspar sandstone.

With pottery you either find a good deposit or have to use very modern methods extract the bits you want.

Earthenware / Terra Cotta is producable from normal kilns and magma kilns.  Magma kilns can produce these products with no fuel, as they "only" need to be cooked at 900-1100 degrees celcius.  Such kilns can also be used for second-fire glazing, since most of these don't require more than 1100 degree celcius fires, either.  This tier of goods could produce bricks and shingles from common soil types.  This could actually be fairly useful on aquifer levels, or useful for humans who don't have stone.  Pottery made from earthenware levels can be used as a special type of barrel (Jugs or some such special name), however, only if glazed in some way.  The easiest type of glazing would be that ash glazing style, which would simply require throwing some wood or ashes in the kiln with the pot, possibly with some additional material that actually makes the glaze (sand? salt? feldspar powder?).  These jugs could make a good replacement for barrels, although they may, perhaps, need to be "stacks" of jugs to hold the same volume a barrel would hold.  It would be better, however, if ash (or wood) was modded so that we could get several glazings worth of ash per tree, or it still winds up using a tree to make one barrel-replacement (unless you used a metal powder in the glazing).  Such glazes can take place with the original firing.  Earthenware would be cheap (material value 1), and generally good for making practice crafts for your rising potters, as well as making bricks, or other basic materials.  They could potentially make most crafts you can make with stone out of terra cotta, including coffins or statues.  Even better, masonry made of earthenware might hopefully be engravable and paintable, like with many of the extremely decorated facades of real-life temples.

That pretty much works.


Glaze "powders" - you mean the colour pigments?
Those are required in very small quantities and would be ground with a mortar and pestle.

Clay / kaolin / kaolinite is always a powder. Usually anyway.
Would be very funny if you built a wall from kaolinite "stones".
The first rain would turn it into a puddle of mud and wash your wall away...

Stoneware could then be the serious industrial ceramics material - taking several coal units (3 or 5?) to fire the high-temperature kiln (1200-1400 degrees celcius), and requiring the air pump to be mechanically powered, as well as a mechanically powered stone crusher to make the powders.  Stonewares would be highly valuable trade goods, beyond the price of clear glass, certainly, and nearing that of pricy metals (something like 10 or 15 material value?).  Stoneware could have those ash glazes, or more expensive decoration-style glazes, which could use multple glaze powders to boost the decoration value, and even be used to paint detailed scenes with multiple colors, creating a skyrocketing final value.  Stoneware could actually be split a little into a lower-grade and higher-grade depending on if you really work the right materials into the clay.  (5 material value versus 15?)

Works but I'm afraid it's getting too complicated. =)

Actual porcelain would be a highest-tier, require large amounts of fuel (5?) for the fires (1350 celcius), very picky material requirements, and yet be very valuable for the effort (material value 40?).  With a legendary craftsdwarf and 6 or so colors, you might potentially make something in artifact-level (or even mid-sized dwarven syrup roast) values.  This process would require powdered kaolin, powdered feldspar (like orthoclase or microcline), and a source of quartz/silica (powdered granite, sandstone, shale, gniess, quartzite, or just plain sand (? sand could be anything...)) for the main body.

Oh ya, always think about the obvious bits last.
Porcelaine consists of up to 50% (or more) glass. Literally glass.
That's why it's so mechanically unstable during the firing.

Quartz and feldspar (K) are the typical suspects for providing the materials.
That's why it's usually not such a big deal that Kaoline deposits always contain quartz.

[NW_Kohaku]

Sorry if I skip some things, but certain parts caught more of my attention than others...

Glaze "powders" - you mean the colour pigments?
Those are required in very small quantities and would be ground with a mortar and pestle.

Yes, the easiest DF catagory to appropriate is "powders", alongside dyes (and flour), so I was just trying to put it into game terms.

I already had hoped that powdering an ore would provide very large amounts of pigment for glazing (although maybe less so for ash glazing), with something like 10 or 20 powders in a stack per ore.

Usually you only use sand (different kinds of) and maybe around 10% of clay.

Funny how there is a boatload of different "rocks" but only 3 or so types of sand.
For every rock there is also a sand. =)

For glazes you'd use quartz and feldspar sand. Usually you get both at once.
That you only need "sand" to create glass in DF isn't that far from the truth.
You're just lucky to get a meltable mix every single time. =)

The melting point is defined by the recipe and which kind (Na, Ca, K) of Feldspar you use.

For Porcelain you'll mostly want potash(orthoclase), for earthenware albite (Na).
Calcite is somewhere in the middle. For stoneware you'll use a mix of K and (Na/Ca).
And no feldspar is ever pure. You always get a mix of several ones.

Ugh, I'm looking for alternatives, here... Albite isn't even in DF.

So, if we are looking for something with the right chemical composition, and sand isn't available, is it possible to just grind up a certain kind of feldspar, or a combination, and try to get something in the right ballpark of where we need to be?

Also, the Wikipedia link said that you could add flux material to modify the melting points - would a powdered feldspar of a certain stone become acceptable by adding a flux material to the mix, like that chalk/limestone/other flux or potash or salt (which would be Ca, K, and Na...)?

Oh ya, always think about the obvious bits last.
Porcelaine consists of up to 50% (or more) glass. Literally glass.
That's why it's so mechanically unstable during the firing.

Quartz and feldspar (K) are the typical suspects for providing the materials.
That's why it's usually not such a big deal that Kaoline deposits always contain quartz.

In which case, we just make porcelain just be kaolin and sand?  If there is any sand-substitute, it would have to work for glass, as well?  I don't really mind restrictive material requirements too much, but making it the exact same restriction as applies to glass just tells people "sand in your map, or don't even bother"... people are already like that with glass, anyway.

[Gazz]

So, if we are looking for something with the right chemical composition, and sand isn't available, is it possible to just grind up a certain kind of feldspar, or a combination, and try to get something in the right ballpark of where we need to be?

Well, in DF you could grind down any stone to create "sand".
DF sand is unique in that it is always the correct mix for every application - like glassmaking. =)

Also, the Wikipedia link said that you could add flux material to modify the melting points - would a powdered feldspar of a certain stone become acceptable by adding a flux material to the mix, like that chalk/limestone/other flux or potash or salt (which would be Ca, K, and Na...)?

Feldspar is a flux material at these temperatures.

In which case, we just make porcelain just be kaolin and sand?  If there is any sand-substitute, it would have to work for glass, as well?  I don't really mind restrictive material requirements too much, but making it the exact same restriction as applies to glass just tells people "sand in your map, or don't even bother"... people are already like that with glass, anyway.

Basically that's what is is.
DF is just strange in that there are areas without sand.
On this planet, if there are any minerals whatsoever, there will be sand.

Even on the moon - without any water or atmosphere for erosion - you have sand.
(thermal erosion works if you're not in a hurry =)