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The transparent red spinels were called spinel-rubies [14] or balas rubies. [15] In the past, before the arrival of modern science, spinels and rubies were equally known as rubies. After the 18th century, the word ruby was only used for the red gem variety of the mineral corundum, and the word spinel came to be used. [16] "
Taaffeite (/ ˈ t ɑː f aɪ t /; BeMgAl 4 O 8) is a mineral, named after its discoverer Richard Taaffe (1898–1967) who found the first sample, a cut and polished gem, in October 1945 in a jeweler's shop in Dublin, Ireland. [4] [5] As such, it is the only gemstone to have
Samarian Spinel, the world's largest spinel; Menshikov Ruby, the world's second largest spinel set on top of the Great Imperial Crown of Russia; Timur Ruby, believed to be a ruby until 1851, hence its name; Black Prince's Ruby, the famous spinel mounted on the Imperial State Crown of the United Kingdom
It and a smaller 270-carat (54 g) spinel were captured and taken to Iran by Nader Shah following his 18th-century invasion of India.. The Samarian spinel has a hole in it. According to a diary entry of the court physician to Naser al-Din Shah Qajar, the shah told the physician that the stone once adorned the neck of the biblical golden calf, which the Israelites are said to have made while ...
The Black Prince's Ruby is a large, irregular cabochon red spinel weighing 170 carats (34 g) set in the cross pattée above the Cullinan II diamond at the front of the Imperial State Crown of the United Kingdom. [1] The spinel is one of the oldest gems in the Crown Jewels of the United Kingdom, with a
This is a list of gemstones, organized by species and types. Minerals There ... Spinel. Ceylonite (var.) Spodumene. Hiddenite (var.) Kunzite (var.) Triphane (var ...
Inverse spinel structures have a different cation distribution in that all of the A cations and half of the B cations occupy octahedral sites, while the other half of the B cations occupy tetrahedral sites. An example of an inverse spinel is Fe 3 O 4, if the Fe 2+ (A 2+) ions are d 6 high-spin and the Fe 3+ (B 3+) ions are d 5 high-spin.
Galaxite is the manganese (Mn) rich endmember of the aluminium (Al) series of the spinel group. Divalent iron (Fe) and magnesium (Mg) readily substitute for the manganese in the crystal structure. Trivalent iron may also substitute for the aluminium. Thus, reflecting most natural samples, the formula may be better represented as (Mn,Fe 2+,Mg ...