I guess I should not be irritated with all the posts asking for a valuation based on a photo. After all, the people who post these requests are the people who keep this forum in business. However, it might help a little if they were to bear a few things in mind.
Gemstone sellers are in business to make money and they are generally either very well educated about gemology or at least savvy as to current prices for the materials they sell. If you have to ask what the value of a gem or mineral is, you obviously don’t know your gems and minerals. So you are an uneducated buyer buying from a savvy seller. In this situation, the absolute best that you can hope for is that the seller will give you a fair retail price. As soon as you buy the gem or mineral, you have lost money, because you, a customer, cannot resell the material for a retail price. Your selling price will probably be somewhere between wholesale and retail, and toward the wholesale end.
Bearing the above in mind, you need to banish all thoughts of making money buying and selling gems and minerals until you have become educated as to ID and value and market forces. This is going to take you a good while. Gemology is not that hard to learn, but takes time, probably a couple of years or so. As to valuation, that takes experience judging clarity, color, etc. and often that is hard to come by, since you are not buying and selling quantities of gem materials daily and your access to markets overseas may be limited.
Your best route to making money in gems is going to be learning a lot about how gems are fashioned and how jewelry is made, how gems and jewelry are marketed, etc. It isn’t impossible to do, but it does take a lot of time. If you take the time to learn how to buy rough gems wisely and learn to cab and/or facet, you can make some money, because now you are buying rough at wholesale (in bulk) and then fashioning it and mounting it for sale at a retail price.
I hope this is somewhat helpful. We could discuss various gems and how they are cut, what the yield is, how they are mounted and sold, etc., but that would be the subject of other posts… -royjohn