If you are dealing with a large volume of stones, it’s not worth the time to learn and inspect each stone by yourself. The idea that Troy J has provided is the best for high voumes. A staff or even a partime gemmologist is worth paying to separate the good, the bad, and the ugly. Using outside services must be reputable organisations. Removing stones must be ideally done by a jeweler. Cracking or chipping stones during removal is a big loss. If you are a large scale business, investing in jewerly making and stone selling may take sometime to become profitable. However, this is another option.