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12 Cards in this Set
- Front
- Back
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What two forms does zircon occur in |
High type or low (metamict) |
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What is Zircon? |
Zirconium silcate containing traces of uranium, thorium and the rare earth elements ZrSiO4 |
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Zircon crystal structure is? |
High type tetragonal Low type amorphous Habit is prismatic |
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What type of twinning occurs in zircon |
Geniculate twinning |
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What colours do zircon come in? |
High red, brownish orange, colourless, heat treated blue, yellow/golden Low green, also brown, orange, yellow |
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Zircon is found in what locations? |
Thailand, Ceylon and Burma |
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Zircon hardness |
High type 7-7.5 Low type 6-6.5 Zircon is known for parcel wear |
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Zircon fracture |
Conchoidal |
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Zircon under chelsea filter |
Green shows red Blue shows green |
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Zircon under UV |
Short wave - inert to mustard yellow Long wave - inert to mustard yellow sometimes yellow orange |
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Zircon under spectroscope |
Uranium line at 653.5 (orangutan line) And picket fence |
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What does heat treatment do in zircons |
Heat treatment at 1450° helps to partially recrystallise metamict zircons and results in a higher specific gravity and absorption spectrum also sharpens. Never get complete restoration of structure |
