You start w/big rocks, yes. Big rocks are a mixed blessing. They're a way for the devs to give your initial base extra space from facilities you can't immediately replicate, but not TOO much extra space. You can then open that space by selling them off, or
grinding them up with runts. There's an 84% chance you'll just get 50 small rocks from crushing them, 6% chance you'll get metal ore you can refine into scrap metal, 4% rare earth elements, and the remaining 6% is split between precious metals, hellerium, gems, coins, and goodie boxes.
You can eventually mine more big rocks to break down into this stuff as well if you have the runt power to spare. I wanna say one of the Captain specializations eventually lets you process them more efficiently. [Edit: yep, ?Jackass Captain? lets you
mine and
process them twice as fast with guaranteed good item output, but w/o getting a chance at boxes, and also with guaranteed Hideout Cleanup Bills and a small chance at demonic incursions...]
Some of the regional starts give you fines right off the bat. Look in the online Bootypedia under the
STARTING BONUSES section to see what good and bad things your location/region combo gives you.
Eurasian Autonomy gives you one fine. Rogue Fields gives you 5. Cali gives you 50 Hideout Cleanup Bills. Those are all country starts. WRT regional starts, Central Asia gives you 777 Capitatory Taxes, which is brutal.