Gemmology is the art and science of examining gemstones in depth to analyse their physical and chemical properties, discover their origin and understand their beauty.
There are more than 3,000 minerals, but only around fifty are considered as being of "gemstone quality" and can therefore be used in jewellery-making.
International legislation lists gemstones according to three classifications:
1. The 4 precious stones which are diamonds, rubies, sapphires and emeralds.
2. Semi-precious stones referring to transparent gemstones such as aquamarine, garnets and amethysts
3. Ornamental stones and organic substances
Ornamental stones: translucent to opaque gemstones (agate, lapis lazuli, etc.)
Organic substances: gems produced by living organisms (pearls from shells, ivory from elephants, coral from polyparies, etc.).
There are significant variations in hardness between different minerals. Hardness means the resistance of a gemstone to corrosion, scratching, abrasion and thermal or mechanical shocks.
Knowledge - Gemmologie |
