| 41. | There is an ancient balas ruby ( technically spinel ) mine at Kuh-i-Lal.
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| 42. | Spinel is pronounced " spin-el ", but how do I write this in IPA?
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| 43. | Unlike spinel, taaffeite displays the property of double refraction that allows distinction between these two minerals.
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| 44. | However, ferric and aluminium based spinels are almost entirely homogeneous due to their large size difference.
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| 45. | Trade terms such as balas ruby for red spinel and rubellite for red tourmaline can mislead unsuspecting buyers.
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| 46. | Distinctive accessory minerals include : fluorite, topaz, apatite, spinel, allanite, sphene and cassiterite.
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| 47. | In the past, before the arrival of modern science, spinels and rubies were equally known as rubies.
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| 48. | Mines in the Gorno Badakhshan region of Tajikistan was for centuries the main source for red and pink spinels.
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| 49. | Spinel, another red gemstone, is sometimes found along with rubies in the same gem gravel or marble.
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| 50. | Hercynite is a spinel of regular symmetry and normal cation distribution, but some disorder occurs in its structure.
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