Terminology
A quick definition of some often confusing terms
by Peter J Clark
Precious and Semi-Precious stones
All of the 'precious' and 'semi-precious' stones that you'll encounter have some unique or particularly attractive feature; that's what distinguishes them from other stones. If you're wondering how to tell which are more precious than others, I'm afraid that's a bit of a blurred distinction. Long ago, some of today's semi-precious stones were called 'precious'. As times and discoveries pass, so does this definition.
It seems that 'semi-precious' often describes softer stones, of less value than other, more precious ones. Although the gem trade still uses both terms, it would in fact be better just to call them all 'gemstones'!
Gemstones
A collective term of the most useful kind! This is the name given to pretty much any ornamental stone - whether it be a hard stone, a soft stone, a precious stone, a semi-precious stone... and so on.
Minerals
Minerals are natural solid substances that are found in the earth's crust. They are always non-organic in nature, and most of them have very clear crystal forms. The study of minerals is called Mineralogy (and not minerology as some seem to think).
Crystals
In its broadest sense, a crystal is simply an uniform body that has a geometric (consistently shaped) lattice structure. It is the differences between the lattices of various crystals that give rise to their different colours, specific gravities, refraction indices and other physical properties. The study of crystal forms is called Crystallography (yes -- with two L's).
Rocks
What's a rock? Oh, come on...
Well alright -- a rock is actually any aggregate of minerals. It may surprise you to hear that, technically speaking, pebbles, gravel and even grains of sand are 'rocks'. Strange... but true.
Stones
This one depends upon who you are, and also upon what you think of when somebody says the word "stone". As Walter Schumann and Evelyne Stern put it (in the book "Gemstones of the World" [NAG Press, London])... an architect sees it as being the material used for building houses, whilst a jeweller sees it as being a gemstone. Everyone else probably sees it as being a hard lump of combined minerals that you find in the garden.
Jewels
Another broad term... anything involving a gemstone, particularly that which is ornamental in nature, is counted as a jewel. A jewel will often be a piece of jewellery consisting of gemstones (semi-precious and/or precious) set into a precious metal. But the term can also be applied to gemstones that are unset but are cut.
Copyright © 2000 Peter J Clark
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