A few words of advice. While some of the standard jewelry supply places also carry stones, they are not necessarily the best place to buy them. First, they are likely to carry a limited range of commercial quality and commercially in demand cuts rather than custom cuts or gems that are rarer or finer in quality. Let me put in a pitch here for American custom cutters and for gem dealers closer to the sources in Africa, Thailand and Sri Lanka. It is a lot like picking someone for home improvement. I look for a single craftsman who works alone or with an assistant who comes in an old truck. The minute you call a business, there is a fleet of trucks, employee benefits to pay and an owner taking a cut, sometimes a big one, and often abusing the employees. You do get a guarantee, but at a cost. If you find a craftsman with a good reputation, he will also make good on his work and often won’t have to, because it will be done right the first time.
The same thing applies to the stone business. Everyone who handles the stone has to have a cut…so if you can find a cutting house near the source or, say in Thailand, with buyers who go to Africa and buy in bulk, or a custom cutter in America who has good sources, you are cutting down on the number of people who have to have a cut. Likely you will get better merchandise, which showcases your metalwork and sells better, often for the same price or not that much more than the commercial stuff. If you are looking for agate and such cabs, I would also attend local gem shows and also attend a few meetings of the local gem and mineral club and ask around…you will likely find more than one person who has cabs for sale or even rough from which they will cut for you. Often these are retired folks who are cutting stock which they got years ago cheap and the price may reflect that rather than the replacement cost of inventory.
The American stone cutting world is a pretty small one and many of the cutters are gemologists who value their reputations above all, so you are unlikely to get cheated. You might also try some of the Facebook groups (there are several) where stones are sold. Custom cutters often hang out there and an inquriy might produce what you want.
If you message me privately, I may be able to make suggestions for your particular needs. You don’t say whether you’re looking for $10 agates or $1000/ct emeralds…HTH, -royjohn