1. What Are Minerals?

Minerals
1. Colour - The colour of the mineral as it appears in reflected light to the naked
eye.
A mineral can occur in different colours. This may be caused by the addition of a
particular trace element or by structural irregularities that cause it to absorb and
transmit particular wavelengths of light. Such slightly different versions of a
mineral or gemstone are called varieties. For instance, the mineral beryl comes in a
number of colours - colourless, pink, yellow, orange, red, blue and intense green,
each with a different variety name. The intense green variety is called “emerald”,
the blue, “aquamarine” and the pink “morganite”.
2. Lustre - The character of the light reflected from the mineral. A mineral may
have a metallic lustre (in other words, it’s a metal), or a non-metallic lustre.
Non-metallic lustres may be described as:
glassy or vitreous
dull
pearly
resinous
waxy
adamantine
silky
3. Hardness - The resistance of a mineral to scratching. Hardness is measured on a
scale of 1-10 called Mohs Hardness Scale. In lab, we express hardness in
comparison to common objects (fingernail, copper penny, nail, glass).
The table below is a universally accepted standard of the comparative hardness of
minerals. It’s the Mohs' scale, after Frederich Mohs, the mineralogist who devised
it. The range is from the softest mineral (talc) to the hardest (diamond).
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