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Spinel Gemstone Information

Spinel is thought to come from the Latin word for 'Spark' referring to its colour, or Greek for 'thorn' or 'point' with reference to its octahedral (double pyramid) crystal form. Octahedral diamonds were also called point stones in ancient times.

Spinel is a hard and durable gemstone with a bright vitreous lustre, it is available in many colours. An ideal and attractive stone for jewellery.

Red spinel is so similar to ruby, that many of the famous rubies set into crown jewels and private jewellery collections were later proved to be spinel. The event of chemical analysis and gemmological testing methods proved spinel and ruby to be chemically different and belonged to different crystal systems. Spinel belongs to the cubic system (isometric) and is singly refractive and ruby belongs to the trigonal crystal system (anisotropic) and is doubly refractive.

Source locations for spinel include: Africa, Afghanistan, Cambodia, Myanmar (Burma), Russia, Sri Lanka, Thailand and Vietnam.

Physical Properties

Stone type:
Spinel.
Crystal System:
Cubic (isometric).
Chemical Composition:
Magnesium Aluminium Oxide, MgAl2O4.
Colour:
Red, yellow, brown, blue, green and black. Near colourless stones also occur.
Lustre:
Bright vitreous.
Pleochroism:
None.
Dispersion:
Medium.
Hardness:
8 on the Mohs' scale of hardness.
Toughness:
Good.
Cleavage:
Indistinct.
Density in gm/cc:
3.58 to 3.61
Double refraction:
None.
Refractive index:
1.712 to 1.740

Common Treatments

Spinel is not normally treated.

Synthetic spinel is manufacturered, some are made to simulate other gemstones including ruby, sapphire and alexandrite.


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