Which mineral has the same hardness as a fingernail?

Question

Which mineral has the same hardness as a fingernail? a. diamond c. fluorite b. topaz d. gypsum

Prof. Zackary Crist MD · Accepted Answer

Gypsum has the same hardness as a fingernail

Prof. Zackary Crist MD · Answer

GypsumExplanation:                    The hardness of minerals or substances is measured qualitatively using Mohs Scale. In this scale the hardness is measured qualitatively by characterizing the resistance shown by one substance when rubbed against second substance. Therefore, greater points are given to those substances which are capable of making scratches on other substances. The Mohs Scale of given compounds is as follow,                                      Diamond          10                                      Fluorite            4                                       Topaz                8                                       Gypsum            1.5 to 2While the hardness value of Fingernail is 2 to 2.5. Hence, this value is close to Mohs scale hardness value of Gypsum therefore, gypsum is the correct answer.

Prof. Zackary Crist MD · Answer

Option (C) Explanation:The hardness of any material depends upon the type of chemical bonds and the energy requires to break that bond. Diamond and graphite has covalent bonding between their carbon atoms. Gary rubs the diamond the graphite piece is scratched because diamond has strong covalent bonding then graphite. The bond energy of diamond is much higher than graphite. Gary rubs the piece of graphite against diamond, diamond doesn't scratch because diamond is harder than graphite.Thus, the correct answer is option (C).

Prof. Zackary Crist MD · Answer

C ) The diamond is harder than graphite !!

Prof. Zackary Crist MD · Answer

Calcite or gypsum...

Lori Robel

Which mineral has the same hardness as a fingernail?

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