Antimony-bearing Tulameenite

The kinds of rock environments where the mineral typically forms — igneous, metamorphic, hydrothermal, sedimentary, pegmatitic, and so on.

Resistance to being scratched, ranked on the Mohs scale from 1 (talc, marked by a fingernail) to 10 (diamond, scratches everything below it). The classic field test.

Whether and how much light passes through a mineral, from transparent (you can see through it) to translucent, then opaque.

The hue of the mineral itself. Often unreliable for identification — many species occur in several colours depending on trace impurities or radiation damage.

How a mineral resists breaking, bending, or crushing. Brittle snaps cleanly, malleable hammers into sheets, sectile slices like soft metal.

One of seven geometric families that describe a mineral's atomic symmetry: isometric (cubic), tetragonal, hexagonal, trigonal, orthorhombic, monoclinic, triclinic. Two non-crystalline classes — amorphous and icosahedral — also appear.

The crystal habit observed at the type locality — the place where the mineral was first described.

Chemical elements that make up the mineral's ideal formula, listed by atomic symbol with their share of the total mass.