Shape - do the crystals have well defined edges and angles (euhedral), or are they rounded (anhedral), or something in between (subhedral)? Are the xtals square, oblong, hexagonal, etc?

Form: crystalline, prismatic, massive, arborescent (tree like), reniform (kidney shaped), bladed, wiry

Crystal symmetry: planes, centres and axes (2,3,4 & 6 fold)

Transparency - transparent, translucent or opaque

Lustre - how the mineral reflects light: vitreous (glassy), dull, earthy, silky, metallic. Some metallic looking minerals will eventually tarnish, such as Pyrites.

Hardness (Moh’s Scale of soft to hard from 1 to 10 ) - a hard mineral can scratch a softer one. Try comparing them with your fingernail, a copper coin and a penknife blade.Do not use this test on good museum-quality specimens!

Density - does it feel heavier of lighter than it looks? Density can be measured to give an accurate figure.

Fracture - the shape of a broken edge; can be -conchoidal (like glass), uneven, even

Cleavage - a tendency to split, can sometimes be seen as fine lines on the crystal face. If the crystal was broken it would probably break along the cleavage. Cleavage can be in more than one direction and is described as being absent, poor, moderate, or good (bad news if you drop it!)

Twinning - are two or more crystals linked together or interpenetrating?

Taste - some minerals have a distinctive taste, such as Halite (Rock Salt). But some are poisonous, so use this test with care!

Feel - some minerals have a particular feel to them: soapy or waxy.

Smell - some minerals have a particular smell to them, especially when freshly broken, e.g. Sulfur