Ads
related to: spinel gemstone definition and benefits and properties of light and sound
Search results
Results From The WOW.Com Content Network
Polyhedral representation of spinel MgAl 2 O 4. Spinel (/ s p ɪ ˈ n ɛ l, ˈ s p ɪ n əl / [7]) is the magnesium/aluminium member of the larger spinel group of minerals. It has the formula MgAl 2 O 4 in the cubic crystal system. Its name comes from the Latin word spinella, a diminutive form of spine, in reference to its pointed crystals. [5]
Ceylonite, named for the island of Ceylon, is a ferroan spinel with Mg:Fe from 3:1 and 1:1, and little or no ferric iron. Pleonaste is named from the Greek for 'abundant,' for its many crystal forms, and is distinguished chemically by low Mg:Fe ratios of approximately 1:3. It is sometimes used as a gemstone. [2]
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 ...
The confusion between spinel and taaffeite is understandable as certain structural features are identical in both. Anderson et al., [7] classified taaffeite as an intermediate mineral between spinel and chrysoberyl. [9] Unlike spinel, taaffeite displays the property of double refraction that allows distinction between these two minerals.
Main page; Contents; Current events; Random article; About Wikipedia; Contact us; Pages for logged out editors learn more
Sources from the times of the Russian Empire differ in the definition of the stone that topped the great imperial crowns of Russian emperors and empresses: some of them define it as a true ruby, a precious red corundum (“oriental ruby”, “yakhont”, “red yakhont”), [9] [10] and others define it as “lal”, [6] [11] that is, spinel ...
Other gems also occur in colour-change varieties, including (but not limited to) sapphire, garnet, spinel. Alexandrite displays a colour change dependent upon light, along with strong pleochroism . The gem results from small-scale replacement of aluminium by chromium oxide, which is responsible for alexandrite's characteristic green to red ...
The Jaredites placed a stone fore and aft on each ship and had "light continually" during their 344-day voyage to America (Ball 1938: 500). The theme of luminous gems guiding mariners and others originated in Europe in the Middle Ages. The earliest is probably the Scandinavian saga of the Visby garnets.