As I mentioned earlyer, I was given a small light box, but often this box doesn't offer enough light, So i would use it in conjunstion with natural light and a handheld mirror place off camera then used to redirect soem of the natural light. The light box measures 6'' x 6'' and sits flat on a table top so it is also portable. But I've never found any use for the light box other thna takign pictures of shoe sting facted gems stones.
Image of a home made/faceted (Shoe Sting Faceting) blue oval topaz. In order to hold the gem, I used a desktop/table mount adjustable lacross tweezer