Which material is identified as the softest?
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Answer: B. Calcite
Explanation
Calcite has a Mohs hardness rating of three on the standard mineral scale. Its crystal structure features relatively weak ionic bonding between calcium carbonate layers. This softness allows calcite to be easily scratched by copper and steel tools. Calcite is a common rock-forming mineral found extensively in sedimentary limestone deposits. The Mohs hardness scale uses ten reference minerals to measure relative scratch resistance. Soft minerals are easily abraded during geological weathering and mechanical processing.
Geologists use simple scratch tests with common items to identify mineral specimens. Limestone and marble structures composed of calcite weather relatively quickly outdoors. Industrial filler applications utilize ground calcite due to its softness and abundance. Quartz has a Mohs hardness of seven making it much harder than calcite. Fluorite rates four on the Mohs hardness scale which is harder than calcite. Corundum has a Mohs hardness of nine representing an extremely hard mineral.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
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