The name pyrope comes from the Greek word meaning “firelike”, and this variety of garnet is tipically red. Precious beads pyrope is less common than most garnets, but it is widely used as a gemstone. It is coming from the class of silicates with isolated silica units. Precious beads pyrope is difficult to distinguish from almandine without a spectroscope, but it is usually displays fewer flaws and inclusions. High-chromium varieties from volcanic pipes (such as diamond pipes) are known as chrome pyrope. The crystal system is cubic and it is composed from magnesium aluminum silicate.
The main sources are in Tanzania, Italy (Dora-Maira Massif), Brazil, South Africa, Australia, Czech Republic (Bohemia), and USA (Arizona). Precious beads pyrope’s luster is greasy to vitreous and its fracture is conchoidal. Colors available are in shades of red and sometimes colorless to pink for very pure examples. Both of the cleavage and birefringence are none and the dispersion is 0.022.
Red precious beads pyrope is very dark in tone, or occurs in small sizes (so-called “ant hill garnets”). Because of this, gems are rarely faceted (as mixed or brilliant cuts) in sizes over one carat. Stones over two or to three carats are the most valuable. American and South African precious beads pyropes are lighter than those from Bohemia, lighter, brighter stones are most expensive than darker stones, with pale pinks and reds, and brighter reds, purples, and pinks commanding the highest prices. The very light pink precious beads pyrope came from the Dora Massif are often shattered and so rarely occur as large stones. The hardness stopped at level 7-7.5.
Nearly all precious beads pyrope comes from ultramatic igneous rocks, which also contain olivine and/or diamond. Its habit is dodecahedral or trapezohedral crystals. Metamorphic precious beads pyrope occurs as a natural gemstone when these igneous rocks are metamorphosed, and also from rocks that are rich in magnesium. The refractive index of precious beads pyrope is between 1.715-1.75 and the specific gravity is between 3.51-3.80. Almandine and pyrope comprise a series which iron replaces the magnesium in pyrope. In fact, the pure precious beads pyrope is very rare in nature and the various proportions of the two minerals are known as pyrope-almandine mixes. One intermediate stone between the two is the variety called rhodolite, which is a rich-red purple colored stone. A rare intermediate between precious beads pyrope, almandite, and spessartine is a color-change garnet from Madagascar, which is blue in some lighting.
Saturday, July 2, 2011
Monday, June 27, 2011
Crystal Stone Padparadscha Sapphire
Padparadscha (sometimes spelled padparadshah) is an orangey pink sapphire (corundum). It is coming from the class of oxides and hidroxides. With a 0.008 birefringence and 0.018 dispersion, this very rare crystal stone padparadscha sapphire is valued for its attractive color. The most important deposits are located in Sri Lanka; some Vietnamese pink sapphires, and African red-orange sapphires come close to being padparadschas. Crystal stone padparadscha sapphire has trigonal system and composed from aluminum oxide. The name derives from the Sinhalese word for lotus blossom. Naturally colored (unheated) crystal stone padparadscha sapphire is among the rarest and most highly valued corundums in the world. Sri Lanka is the main producer for this gemstone.
Crystal stone padparadscha sapphires are one of the world’s most expensive gems, and prices are comparable to those fetched by fine rubies or emeralds, and even diamonds. Its habit is steep hexagonal bipyramids. Crystal stone padparadscha sapphires must have greater clarity than an equivalent ruby because inclusions seem to be more prominent in a padparadscha saphire. The luster is adamantine to vitreous and the hardness is at level 9. Crystal stone padparadscha sapphire gemstone has a weak-basal-parting cleavage and conchoidal fracture.
However, crystal stone padparadscha sapphires are rarer than rubies, and because they are usually only found in stones of well under two carats, they are highly prized and expensive. With 1.761-1.769 refractive index and specific gravity 3.98-3.99, the deep, saturated colors of crystal stone padparadscha sapphire are more valuable. Stones are normally faceted as a mixed cut, Beryllium-diffused (treated) pinkish orange sapphires are sometimes incorrectly called padparadschas.
A large majority of crystal stone padparadscha sapphires (and most other colors of sapphire) are heated to deepen the color and improve the clarity. The color of this amazing natural gemstone comes from trace quantities of both iron and chromium. The largest gem-quality crystal stone padparadscha sapphire was a 1126-carat crystal found in Sri Lanka in the mid 1980s. A large faceted example weighs 100.18 carats and can be found in the New York’s American Museum of Natural History.
Crystal stone padparadscha sapphires are one of the world’s most expensive gems, and prices are comparable to those fetched by fine rubies or emeralds, and even diamonds. Its habit is steep hexagonal bipyramids. Crystal stone padparadscha sapphires must have greater clarity than an equivalent ruby because inclusions seem to be more prominent in a padparadscha saphire. The luster is adamantine to vitreous and the hardness is at level 9. Crystal stone padparadscha sapphire gemstone has a weak-basal-parting cleavage and conchoidal fracture.
However, crystal stone padparadscha sapphires are rarer than rubies, and because they are usually only found in stones of well under two carats, they are highly prized and expensive. With 1.761-1.769 refractive index and specific gravity 3.98-3.99, the deep, saturated colors of crystal stone padparadscha sapphire are more valuable. Stones are normally faceted as a mixed cut, Beryllium-diffused (treated) pinkish orange sapphires are sometimes incorrectly called padparadschas.
A large majority of crystal stone padparadscha sapphires (and most other colors of sapphire) are heated to deepen the color and improve the clarity. The color of this amazing natural gemstone comes from trace quantities of both iron and chromium. The largest gem-quality crystal stone padparadscha sapphire was a 1126-carat crystal found in Sri Lanka in the mid 1980s. A large faceted example weighs 100.18 carats and can be found in the New York’s American Museum of Natural History.
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