Properties of Talc

Talc is a mineral that is composed of magnesium, silicon, and oxygen, and it belongs to the phyllosilicate group. It is known for its characteristic softness, smoothness, and a greasy or soapy feel. Talc is the softest mineral on the Mohs scale of mineral hardness, with a rating of 1.

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Image of talc mineral
Credit: Rob Lavinsky, iRocks.com - CC-BY-SA-3.0, via Wikimedia Commons

The following table provides a comprehensive list of talc properties in both SI and US customary/Imperial units at normal temperature and pressure (NTP).

Note: click on the button to switch between Metric and Imperial units.

Table of Talc Properties
Physical Properties
Metric
Chemical FormulaMg3Si4O10(OH)2
Molar Mass379.266 g/mol
Crystal SystemMonoclinic
Mohs Hardness1
Density2580 - 2830 kg/m3
ColorPale green, white, gray white, yellowish white, or brownish white
DiaphaneityTranslucent
LusterVitreous (glassy), pearly
Cleavage(001) perfect
FractureUneven
StreakWhite

Note: unless stated otherwise, all values are taken at room temperature (approximately 20°C or 68°F) and 1 atm pressure. (1 atm = 101,325 Pa)

Related Pages
References: 1) Cardarelli, François. Materials Handbook: A Concise Desktop Reference. Switzerland: Springer International Publishing, 2018. 2) CRC Handbook of Chemistry and Physics, 97th Edition. United Kingdom: CRC Press, 2016-2017.