Lustre is entirely independent of colour of mineral. A deeply coloured mineral may be lustreless and vice-versa.

Idiochromatic having a characteristic, fairly constant colour related primarily to composition of mineral. Metallic minerals belong to this category.

Colourless and transparent minerals will always give a colourless streak that has no significance. The coloured and opaque minerals, especially of ore groups, give typically characteristic streaks quite different from or similarly looking minerals.

When mineral is in form of a thin or thick elongated, column-like crystals, it is said to be elongated. For example, Beryl.

The colour of muscovite mica is usually colourless to pale yellow but gives no streak.

The foliated structure is similar to lamellar in broader sense but in this case, individual sheets are paper thin, even thinner and can be easily separated. Example: Muscovite mica.

The olivine mineral is found in olive green colour and hence its name. The streak given by olivine is white.

Quartz minerals are found in wide range of rocks. They are not restricted to any one kind of rock. They may be found in igneous or sedimentary or metamorphic rocks.

A scale of fusibility has been suggested by Von Kobell. It consists of six minerals arranged according to temperature of fusion. Stibnite, Natrolite, Alamandine, Actinolite, Orthoclase and Bronzite.

Some common forms of corundum used as precious or semi-precious gemstones are ruby, sapphire, oriental emerald and oriental topaz. Diamond is a completely different mineral and is not considered to be a form of corundum.