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.

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 icon to switch between Metric and Imperial units.

Table of Talc Properties
Physical Properties	Metric
Chemical Formula	Mg₃Si₄O₁₀(OH)₂
Molar Mass	379.266 g/mol
Crystal System	Monoclinic
Mohs Hardness	1
Density	2580 - 2830 kg/m³
Color	Pale green, white, gray white, yellowish white, or brownish white
Diaphaneity	Translucent
Luster	Vitreous (glassy), pearly
Cleavage	(001) perfect
Fracture	Uneven
Streak	White

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)

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.