While De Beers may vigorously extol the virtues of diamonds as girls’ best friend, few voices extol the virtues of humble talc as everyone’s best friend. Ever heard of diamonds easing diaper rash?

As it sprinkles out of the can talc hardly behaves like a rock or a mineral with its silky smoothness. At H1 on Mohs scale and perfect basal cleavage these tiny flakes of mineral are familiar to all of us.

Since we’re clamoring to know it, the formula for this "acid metasilicate" is Mg3Si4O10(OH)2. Other heavy data include; it’s a phyllosilicate with a hexagonal double-sheet structure with weak, balanced electrical bonds. These allow the familiar slipping of the tiny leaves along a perfect cleavage direction i.e. its greasy softness. Egad.

When more or less pure, talc is considered to be, well, talc. In massive form and colored apple green to brown–black–green it’s usually called soapstone or steatite. Useful deposits may be scarce but it’s really rather a common mineral, the alteration product of often dolomite but also ultra-basic or mafic minerals as olivine, (peridot to gem collectors) serpentine, asbestos, actinolite, tourmaline and magnetite all associated with so-called mafic minerals – those rich in iron (Fe) and magnesium (Mg) and low in aluminum (Al) and silicon (Si). Its structure seems unable to accept Fe or Al, as in chlorite, resulting in a constant pure composition. Oddly, talc and steatite are seldom found together. Pyrophyllite, an aluminum silicate i.e. not magnesium, is often used as a substitute for tale.

In summary, talc is light to white, very greasy to the feel, H1 and SG 2.7.

Soapstone (steatite) is massive i.e. in relatively large deposits, impure, coarse to fine texture, gray to greenish, H1.5 and SG 2.5.

Long a favorite of sculptors, ancient to modern, the soft stone is easily worked with simple tools. But it also has many industrial uses. Some of them: toilet powders (see, I told you!) soaps, leather dressing, waterproof cement, ceramics, dry lubricant e.g. in car door locks, filler in paint, paper, rubber, roofing and insecticides. It marks iron, glass, fabric and – if you are old enough to remember! – pencils used on our school slates.

According to our esteemed former president, Court Saunders, who knows just about every gopher hole and mine over a vast area, Madoc Ontario is one place with significant deposits of steatite in Canada. Another is Broughton, Quebec. This is a major source of soapstone air-lifted to the far Arctic for the Inuit craftspeople, closer sources (Devon Island?) having been exhausted.