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Understanding Soapstone

We have included this section for those who like to get into the details and want a better understanding of what makes this stone so unique.  Soapstone (also known as steatite, or soaprock) is a talc-schist, which is a type of metamorphic rock.  It is largely composed of the mineral talc and is thus rich in magnesium.  It is produced by dynamothermal metamorphism and metasomatism, which occurs in the zones where tectonic plates are subducted, changing rocks by heat and pressure, with influx of fluids, but without melting.  Soapstone has been used as a medium carving for millenniums.

By mass, pure steatite is approximately 63.37% silica, 31.88% magnesia and 4.74% water.  It often contains small quantities of other oxides such as CaO or Al2O3.

Soapstone is relatively soft because of its high talc content, talc having a definitional value of 1 on the Mohs hardness scale.  Softer stones may feel similar to soap when touched, hence the name.  There is no fixed hardness for soapstone because the amount of talc it contains varies widely, from as little as 30% for architectural grades such as those used on countertops, to as much as 80% for carving grades.

The stone also has a high fusion point, low electrical and thermal conductivity and great heat retention. These properties make soapstone invulnerable to most physical damage. It will virtually last forever.

The best architectural grades of soapstone predominantly comes from Brazil, Canada, USA and Finland.