Soapstone or serpentine -- and why would it matter?

14 years ago

Ok, my green soapstone saga continues. The slab I like best locally is generically termed "green soapstone" (no other name) and was quarried in Brazil. There are 30 slabs of it, with only the early numbered slabs containing mostly green. The rest are more the charcoal grey (with MAYBE a slight tinge of green). From the pictures that people have posted here of their soapstone countertops, it looks very similar in terms of color and veining.

The couple of fabricators I'm considering working with are quite adamant that this stone is not soapstone, but serpentine. As far as I can tell, they're basing this judgement solely on the fact that it's green.

Honestly, I'm no soapstone purist (or expert). I was interested in soapstone not only for the deep emerald green color that I've seen in so many pictures (and many of the slabs I've looked at), but also for it being non-porous, non-reactive to acids, the nice matte finish, the easy DIY repair for scratches (sandpaper), and the fact that it doesn't need to be doused with a mystery chemical soup periodically to keep it sealed.

So what if this stone is really serpentine? What does that mean? I have a sample of this stone and have tested it exhaustively for staining and acid issues, which it's passed with flying colors. I can sand the surface easily with sandpaper and it still looks good. I've oiled it dozens of times. So, practically speaking, what's different between serpentine and soapstone (other than the minerals in the stone)?

One of the guys who's insisting this stone is serpentine told me today that serpentine doesn't take oiling very well and that it will be blotchy when you oil it. Since I have only a small sample I haven't noticed any blotchiness, although when I first brought it home and oiled it by the next morning it seemed the oil had soaked in considerably in spots as the stone seemed to be dryer in places. But then I've read that when you first start oiling a soapstone you have to oil it quite frequently (even several times a week) as it goes back to grey quickly until the patina starts to develop. When my sample looked a bit dried out in spots the next morning I just figured it was showing what I'd read about newly-oiled soapstone.

I like the properties of true soapstone. If serpentine has the same properties, then I see no reason not to go that route. But this oiling thing now has me scratching my head. I'm wondering if it's time to use those frequent flyer miles and head to someplace like Dorado Soapstone or Teixeira to pick out a slab from people who really know what they're selling?

Anyone have help or advice for me on this? Anyone have serpentine countertops and can tell me if they oil them or have to seal them?

Featured Answer

tatter
Original Author

14 years ago

By the way, while I was googling around looking for information on serpentine-vs-soapstone, I came across this hugely informative thread on GardenWeb, with Mr. Teixeira himself chiming in with his great expertise. If someone's trying to find this same information as me, I'll post the link below --

Here is a link that might be useful: Soapstone/serpentine discussion

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Comments (6)

plllog
14 years ago
Take a cup of water. Throw it on the (upright) stone. If it falls off without wetting the stone, it's likely soapstone. On a flat (horizontal) piece it'll make a mounded shape and not spread. If it trickles down the (vertical) stone and/or leaves a wet spot, if it flattens on a horizontal piece, it's probably not soapstone.

I've never seen soapstone less than 3 cm thick. Serpentine is often 2 cm, though it could be 3 cm.

Oil doesn't soak into soapstone. It kind of sticks to the top. Soapstone is oliophilic--it attracts oils. If you take a dab of butter and smear it on with your thumb, it should stay. When you wash it, especially with a bit of grease cutter, it should come right off.

I have serpentine in my master. It looks and feels more like marble, and is often classed with marbles, though it's a bit harder. Very veiny.

Your translucent ones (the top two) might just be serpentine, on looks. They don't look soapstoney to me.

Oh! Another test! If there's powder where it's cut, that feels like talcum powder (i.e., if there's loose talc), it's a sign you have soapstone. Soapstone is composed mostly of steatite and talc, with veins of quartz. I don't know that I've handled an unpolished cut of serpentine, but most crystaline stone dust feels more sand like.

Wikipedia says "Most serpentines are opaque to translucent, light (specific gravity between 2.2Â2.9), soft (hardness 2.5Â4), infusible and susceptible to acids. All are microcrystalline and massive in habit, never being found as single crystals. Luster may be vitreous, greasy or silky. Colours range from white to grey, yellow to green, and brown to black, and are often splotchy or veined. Many are intergrown with other minerals, such as calcite and dolomite."

Soapstone is heavy. At least mine is.

Susceptible to acids suggests another test. Lemons or vinegar might be interesting.

Soapstone isn't crystaline, it has platelets or something, so it's not brittle like granite, and doesn't need a lot of support.
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canadiansoapstone_gmail_com
13 years ago
Serpentine is found in the same geological formation as soapstone - we have layers of serpentine within our quarry. We sell it as serpentine and not soapstone.

I think the problem is that fabricators and importers label their product as they wish and not necessarily as it is.

Here is a link that might be useful: www.canadiansoapstone.com
Antoinette Reyes
8 years ago
last modified: 8 years ago
I carve stone recreationally. Generally the "hard" soapstones are actually serpentine. As the Canadian soapstone person above mentioned they are found in the same layer. True soapstone can be scratched with a knife being a 2-5 on the Mohs hardness scale. Anything harder is mislabeled and is serpentine. And they have similar properties as geologically they come from the same layer and are both metamorphic rocks. The main difference is serpentine has less talc in it. Most used in construction are actually serpentine because the stone is harder. Soapstone is more for sculptures.
Tyler Pantalone
8 years ago
Serpentine is a highly variable stone, in appearance as well as hardness. Soapstone is normally between 1 and 2 on mohs scale(sometimes a bit harder), and can usually be marked with a fingernail. Serpentine cannot be marked by a fingernail, but often can with a blade. Hardness can range from 2.5 to 5.5 or so. As far as using for counteracts, I don't know. I have carved enough soapstone, but relatively little serpentine, and with the variability of BOTH stones, it's hard to define properties in a general sense. Testing, as you have done, with a given sample, is the best idea. Soapstone always held up well in pot pipes, I'll say that! Serpentine, too. I've always thought soapstone to be an odd choice for counteracts, given the softness, but I've actually never SEEN a soapstone counterpoint, and I know it's said to be a wonderful material for it. Anyways, just thought I'd throw in whatever knowledge I had on the subject.

Good luck
Tyler Pantalone
8 years ago
Oh! Realize now that the o.p. is probably already past the need for advice!