Spinel has always been regarded as ruby in the past, because it usually co-exists with ruby, and its appearance resembles ruby. Some famous rubies in history are actually spinels. 例えば, the Black Prince’s Ruby in the British crown and the Timur Ruby inlaid on a diamond chain are actually red spinels. 石. Spinel used to be called “Balas ruby”. Balas is the name of Badakshan in northern Afghanistan. 中世の間, the huge local spinel was used as ruby. To this day, people still call red spinel “ルビー “Ruby Spinel” (Ruby Spinel).
The origin of the name Spinel is still uncertain. There are two more credible theories: one is derived from the Greek word Spark, which means fire, which describes its red and fiery color; the other is from the Latin Spina, It means sharp, because its crystalline appearance is cubic crystal system with a sharp angle, so it is named after it.
Spinel has many colors, in addition to red, there are blue, ピンク, 緑, 茶色, そして無色. It is an aluminum oxide containing magnesium. The magnesium in the chemical formula is often replaced by iron or manganese. The common bright red spinel is chromium and iron. Due to the different metal elements, the refractive index value is slightly different, but most of them are around 1.718, only the blue tip The spar will be as high as 1.74, the specific gravity is between 3.58 そして 3.61, 硬さは 8, and the dispersion rate is 0.026.
In terms of inclusions, the clarity of most spinels is much higher than that of corundum gems. The horn-shaped crystal inclusions that often appear in spinel are generally called sequins. They are small spinel crystals, and hyacinth crystals often appear in spinel.
Most of the good spinels in the world are almost all produced in Mogok, ミャンマー. In addition to Myanmar, spinel is produced in Sri Lanka, アフガニスタン, Cambodia and Thailand, そしてオーストラリア, Malaysia, ブラジル, and the United States also have a small amount of production.