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 Cordierite |
| Crystal structure : Orthorhombic |
Composition : Aluminum and magnesium silicate |
| Specific gravity : 2.58-2.65 |
Hardness : 7-7.5 |
| Refractive index : 1.53-1.55 |
Birefringence : 0.008-0.012 |
| Variety : |
Pleochroïsm : very strong (dark blue-purple, pale blue) |
Cut :      |
Blue colouring is due to iron. According to the angle of sight, the color of the stone can pass from blue-purple to gray-yellow. Certain cordierites, known as “iolites with flashes of blood”, have hematite inclusions, their thus giving, according to the direction of observation, red reflections.
Cordierite is not very much used in jewellery. |
| Cordierite takes one's name from the French mineralogist P.L.A. Cordier who was the first studied it. It is called also Iolite because of his moderate color of purple, and also dichroite because of sound strong dichroism. |
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| Deposits : |
| The countries having deposits are : |
Country |
Quantity |
Quality |
Comment |
| Brazil |
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| Burma |
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| Madagascar |
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| India |
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| Sri Lanka |
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