Mysterious boron comes in two allotropes; a brown powder that looks rather identical to something you'd scrape off your shoe and a glassy type that looks like miniature asteroids. Despite being common, boron has a reputation for being fiendishly difficult to isolate into elemental form. So own your own little asteroid and show it off to your friends and family, or don't (and keep your friends and family believing you're of sound mine) and instead brag to your online collecting brethren!

These crystals measure about 3-8mm and are quite porous and lightweight. They are rather rare offerings so you get to have some bragging rights here! Note that 1-gram bottles are too small to hold full size crystals so they will be powdered to fit. Full size crystals are several grams each.

CAS 7440-42-8