Hacking stuff up.
Good to know: Pickaxes can cut more than walls. Trees are also suceptable. As are boulders. And, perhaps most awesomest of all, so are the crystal growths in UT4. These take some doing, though, since your 'axe has to be harder than what you're trying to cut, which basically means you need a meteoric steel 'axe to cut the blue and purple ones, and something stronger to cut the greens. But it's worth it -- ohhh, it's worth it. I've harvested more than 15 stones of different colors from one excursion to UT4 -- and I died before I could cut them all. Purple growths alone give you 3 stones each. Now THAT is how you make money.

Did you try the dwarven gunpowder backpacks on the crystals?

No... I didn't think of that. Do they work?

yes, crystals can be blown up using mines and\or backpacks. I recommend this method, since obtaining a pick-axe hard enough to cut crystal can be a problem. my last character, Jenkins, survived kicking a mine with only minor injuries WITHOUT ANY FIREPROOF GEAR. weird. he also got a green light crystal out of the explosion.

I want to emphasize this again. MINE UT4 IF YOU CAN. I just finished a run down there... I didn't hit up any of the green light crystals, due to an insufficent 'axe, but I still came away with 25 purple, 20 blue, and 1 green stone. I honestly doubt the Attnam shopkeeper will be able to afford them all, even if I bought everything he has that I might want. EDIT: The 25 purples sold for about 1200 gold total. He couldn't afford the blues -- total value of about 2600 -- but still. Also, a quick check revealed that blue stones are more valuable than greens.

can the shopkeepers replenish their gold supply?

Only with your character's purchases.

so I buy everything in the shop, and the owner goes bankrupt. correct?

That wouldn't make sense, because your giving HIM money, and he's dumping off stuff he doesn't want to YOU.

hmmm, let me put it this way: I buy all his stuff, and don't sell anything, then he becomes obsolete.

Yeah, if you have the money for it.

except you can still sell shit TO him. However if you got ahold of 101 CHA, you could buy everything in his shop, then pick one item and sell it back and buy it back etc etc until he has no money. THEN he is obsolete.

Might I suggest you sell those crystal stones from UT one at a time? Each one sells for a different price for some reason, ranging from eighty-something to one hundred forty-something, and more often than not you can sell them for over 120 per stone. Anyone wanna check out whether selling them one at a time gets you a bigger profit?

and i you sell in several times , your charisma should increase more , right ? I think charisma increases a bit for each transaction.

Probably, but the main difference is dropping 20 stones one at a time -- taking a long time and lots of keypresses and lots of boredom -- or droping 20 stones at once, which takes probably 5 or 6 at the most.