Optical Calcite |
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 Technical specifications:
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A very common and widespread mineral with highly variable forms and colours. Calcite is best recognized by its relatively low hardness (H = 3) and its high reactivity with even weak acids, such as vinegar, plus its prominent cleavage in most varieties. The structure of calcite and its related species is ionic and resembles that of NaCl, the place of the spherical Cl ions being taken by planar (CO3)- or (NO3)- groups. These groups are arranged in parallel position in the crystal with their threefold symmetry axes oriented along. This arrangement leads the strong birefringence of calcite-group minerals. |
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Prodotti correlati in: |
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