as a gemstones manufacturer and dealer, i am interested to deliver best quality stones to my clients. i am considering currently over the questions, whether it's good to sell stones which was mined by using explosives or jackhammers. for the explosives i did read, that it can bring a stress factor in the gemstone itself, and he can probably break later easier, also if you dont see that stress from outside in the stones. how would it be for stones mined by jackhammers. also stress factor ? your opinions ?