Kettnerite

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

The place where the mineral was first found and described — by convention, the reference point for the species.

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.

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 full symmetry description of a crystal's repeating atomic pattern — 230 distinct groups, written in Hermann–Mauguin notation (e.g. P6₃/mmc).

The lengths of the unit-cell edges (a, b, c) in ångströms — the smallest repeating box of atoms that builds the crystal.

The number of formula units contained in a single unit cell.

The overall shape and habit a mineral tends to grow into — cubes, prisms, plates, fibres, druses, masses.

Two or more crystals of the same species grown in a fixed symmetric relationship, sharing a plane or axis. Often visible as re-entrant angles.

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.