Many colors for in-game materials were determined before the palettes of the Premium release (Uristocrat, et al.)
With the material diversity of Dwarf Fortress, this means that some materials were left as-is with acceptably minor but unintended graphical consequences.
Ores are the most in need of diversification, with most ore stones being SILVER or GRAY regardless of their actual metal content. Native aluminum is the same material as its smelted counterpart, but has an entirely different color scheme.
The metals made from these ores tend to be distinct in usage, but having more grays (there aren't even definitions for "light gray" and "dark gray") would allow them to overlap in appearance less.
As with all the game palettes, having more grays could also diversify similar-looking layer stones.
New colors could also be based around interesting color ramps. These could be variously designed and applied to gemstones, bismuth, iridescent tissues, or fantastical items.
Gemstones often use many of the same colors, usually based on the name of the gem. Different color ramps have different levels of contrast, so a second pass on assigning palettes to gemstones could take the apparent "shinyness" of real-world samples.
Here are some aesthetic suggestions for specific materials:
- Platinum should have a new color, lighter than silver, but with a sharp color ramp to appear shinier than the standard white color scheme.
- Birch wood's color is quite dark when real lumber is consistently pale. It could be CREAM to match feather wood, or another exceptionally light shade of brown.
- Pig iron would look good in RUSSET, a dark, rusty color to complement its high carbonization.
- Bone and tooth should be color IVORY, taking the color name literally and matches the bone sprite better.
- Rose quartz and rose gold could use ROSE, they have specific colors IRL that are better represented by that palette.
- Mudstone's standard gray doesn't feel "muddy" enough, I would like to see it on a browner shade of gray. Perhaps TAN, perhaps another color.
- For divine materials, all of the yellow colors could use a more vibrant shade of AMBER instead, faceted metal (jewel sphere) could be EMERALD (among other jewel tones), frosty metal (mountains) in PERIWINKLE, searing metal (torture) in BURNT_UMBER, and flowing metal (volcanoes) in DARK_SCARLET.
Armor in various raw colors from a personal helper mod