These are faceted orange GGG, Gadolinium Gallium Garnet. Each is labelled with its weight and letter in the photo and they can be purchased individually.
These have a beautiful light orange color, sort of like a light-toned imperial topaz. It's also a little tenebrescent--exposure to UV intensifies the color while allowing it to sit in the dark for a while returns it to its original intensity.
GGG is an exotic lab-created garnet and an old classic of industry and the gem world. It it was once grown for gem usage, but once CZ hit the scene and got insanely cheap the demand for other gem crystals plummeted. Today it is primarily grown as a growth substrate, a material whose crystal lattice makes it useful for growing other, harder-to-grow crystals on top of it.
In the gem world it is prized for its optical properties, with a dispersion in particular that is very close to that of diamond. Faceted GGGs look very much like a diamond in terms of fire
GGG has a hardness just over 7, is easy to cut and good for use in jewelry though I wouldn't recommend it for a ring.
