GEOLOGY
CRYSTALLOGRAPHY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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{010}
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{111}
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{121}
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{001}
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Detailed explanation-1: -If the compositions surfaces are parallel to one another, they are called polysynthetic twins. Plagioclase commonly shows this type of twinning, called the Albite Twin Law, with 010 as the twin plane. Such twinning is one of the most diagnostic features of plagioclase.
Detailed explanation-2: -Plagioclase. Type of feldspar (framework silicate) that ranges from sodium to calcium rich. The chemical formula is (Na, Ca)Al(Si, Al)Si2O8.
Detailed explanation-3: -The Plagioclase series is a group of related feldspar minerals that essentially have the same formula but vary in their percentage of sodium and calcium. Albite and Anorthite are the end members of the series, with the intermediary minerals Oligoclase, Andesine, Labradorite, and Bytownite.