Cleaning Up Confusion: Metamorphism and the common Soapstone

     My Uncle in Georgia has a really odd countertop in his kitchen. It isn't granite, it isn't marble, it isn't even Gneiss. Instead, it's a rock called Soapstone. I've found a picture which bears a striking resemblance to his countertop, though he only has the drainage lines on one side, and I gotta say: it's weird looking. I can't say exactly what it reminds me of--my first though is "slab" but given that it actually is a slab of rock that's not very helpful--but it makes me think of those black tables from highschool science lab. I've never been very fond of it, but my Uncle loves it and swears it's the best countertop he's ever had. So I was curious what made it such a good building material for countertops. Delving into the topic for the sake of this entry, I discovered some pretty interesting stuff! 
    Soapstone is a fascinating rock. First of all, it's got a lot of talc in it. If you remember way back in Module 1, we learned that talc is the softest mineral, so it's surprising that a stone which ranges anywhere from 30% to 80% talc content is used as a building material. In a way, though, this makes sense. Soapstone (which gets its name from the soft, soapy texture of the more talc-rich varieties) is quite easy to carve due to its soft nature. Additionally, it's incredibly heat resistant, and has been used for cooking purposes for thousands of years now. In other words, if you set a scalding hot pan onto a soapstone countertop, it doesn't have an effect, unlike on some other soft stones common in cabinet construction. The stone is so good for carving that some of the greatest statues ever made, including Christ the Redeemer in Rio de Janeiro.

Before we began calling it the very catchy, easy to remember name of soapstone, it was called by the significantly less catchy name of Magnesiocummingtonite. This is because in addition to talc the stone also contains chlorite and amphiboles like cummingtonite. Why they didn't decide to call it magnesioanthopyllite is beyond me, it sounds way cooler. Altogether, it belongs to the body of metamorphic rocks called Talc-Schist (that's schist with an s) rocks, which you can differentiate from similar looking igneous rocks by looking for crystals spotted throughout the body of the stone and by imaging magnesium and talc melting together under intense pressure. If you can get a sufficient mental image of this happening, then you have no choice but to come up with an image of soapstone in your head. 


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