This just reminds me of skyrim. When i play the game, flawless garnets seem to be worth more...
To be a gemstone, the crystal needs a certain hardness usually over a Mohs 7. Look up the hardness of these stones and determine your own answer.
sphalerite has a lot of luster, and frequent cleavage, so it is really shiny and tends to not be extremely large. it tends to crumble. Quartz has low luster but low cleavage also, and tends to make large crystals. sometimes it is really waxy though, and it is pretty soft. Garnets make nice gems because they have a high index of refraction, really low cleavage, and a high durability. fluorite makes a bad gemstone for it's low hardness and high cleavage, but it makes up for it in my opinion, because it comes in many colors and is phosphorescent. I really like fluorite.
