GEOLOGY
CRYSTALLOGRAPHY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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calcite.
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mica.
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talc.
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graphite.
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Detailed explanation-1: -Talc is the softest mineral on Earth. It is a silicate and it also contains magnesium and water arranged into sheets in its crystal structure.
Detailed explanation-2: -#1 – Talc, the softest mineral, used to make talcum powder and rubber lubricant.
Detailed explanation-3: -Talc: Talc is a phyllosilicate mineral that cleaves into thin sheets. These sheets are held together only by van der Waals bonds, which allows them to easily slip past one another. This characteristic is responsible for talc’s extreme softness, its greasy to soapy feel, and its value as a high-temperature lubricant.
Detailed explanation-4: -The Mohs scale of mineral hardness, based on scratch hardness comparison, defines value 1 as the hardness of talc, the softest mineral.
Detailed explanation-5: -The mineral talc is a hydrous magnesium silicate. A massive talcose rock is known as steatite, and an impure massive variety is called soapstone.