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Ch. 14: Chrysoberyl

Ch. 13: The Spinel Group Page of 187 Ch. 14: Chrysoberyl Text size:minus plus Restore normal size   Mail page  Print this page
the mixed cut. Spinel is also mistaken for garnet or jacinth due to colour, but it has a lower hardness.
Reputed Spinels
Most of the spinels were first taken to be rubies and were latterly recognized as spinels: (1) Rudolph IPs ruby. It was 100 carats in weight and is now said to be a spinel. (2) The ruby set in the crown of His Imperial Majesty is now considered to be a spinel. In the exhibition of 1862, two large spinels were shown. They weighed 197 and carats before cutting and 81 andcarats
respectively after cutting. The French crown jewels also contained a number of spinel rubies, as for instance 56| carats and blue spinelcarats.
Chapter XIV CHRYSOBERYL
Introduction and Physical Properties
CHRYSOBERYL means yellow beryl and it is an ancient name. Its variety, cat's eye, was well-known and appre­ciated from ancient times. It was known as ' Vaidooryam' in India. This mineral was recognized before the discovery of the element beryllium, which is an essential constituent of the mineral. It crystallizes in the orthorhombic system and forms heart-shaped and pseudo-hexagonal twins. These crystals are grown together with interpenetration. The mineral has a pinacoidal cleavage and conchoidal fracture. Hardness = Specific gravity =
Colour varies from pale yellow, brown or green. Lustre: Vitreous and silky in cat's eye. Transparent to trans­lucent. Mean refractive index = Double refrac­tion = and dispersion = Optically positive. Composition: It ranks equally as a precious stone with spinel and there are no other uses.
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Ch. 13: The Spinel Group Page of 187 Ch. 14: Chrysoberyl
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