It is not clear to me what your question is exactly.

Water on soapstone appears visually similar to oil on soapstone, which is why they demonstrated this that way.

If you oil it, it will remain darker for a longish time, until the oil evaporates. This takes probably a couple of weeks at first. (Eventually, the oil polymerizes and so does not evaportate.)

If you get water on unoiled soapstone, the soapstone will remain darkish until the water evaporates (several minutes).

If you get water on oiled soapstone, the appearance does not change much, because the stone is already darkened by the oil. The water will evaporate at the normal rate.

Typically, you do not use a sealer on soapstone, because it is non-porous.

Hope I answered your question among all that.

I've had soapstone in our kitchen for over two years now. Since soapstone doesn't absorb anything (my understanding is that it is an inert substance), water does just sit on top of the surface without soaking in. Ours is unoiled, so when I wipe up the counters, it takes a a minute or two to dry. If I want it to be dry faster than that, I just use a towel. Not a problem at all.

A sealant can also be used, if you use a color enhancing sealant then the stone stays dark and water beads up. Soapstone does not stain so color enhancing sealants are just an easy way to keep the stone dark without oiling or waxing and are a possible way to avoid the water rings that a few people have experienced (not proven, just my theory).

Soapstone in my opinion is a wonderful stone non porous acid resistant. It is soft and may require maintenance overtime. It is pretty straightforward and you may be able to DIY. The most important thing is to fins a great fabricator who can educate the consumer. That way you will know exactly what you are buying-Its characteristics are important to know in making your choice.
Pietra is a different story-much harder to maintain. It is acid sensitive,will scratch and can be very porous.
I know many people who own them. Some do very well with them because there lifestyle doesnt keep them cooking at home. Other who have big families and live a more hectic at home type of lifestyle have had some issues with the stone. Nothing that couldnt be fixed by refinishing the surface.
The geologic name for pietra cordoso is calcareous phyllite.
I have heard it called everything from limestone to granite,even italian soapstone.

If you would go nuts because you had a 20 min wait for water to disappear on unoiled or needing to be reoiled soapstone perhaps you better think about the scratches and dings that may happen. I love soapstone but it isn't a stone for everyone.

This post was edited by eandhl on Fri, Dec 14, 12 at 8:25

Thanks for all the replies. Angie, you did answer my question. Appreciate all the info!

I, too, considered Pietra (PdC) after seeking some intriguing slabs, but was put off when researching the stone. The scratching, staining, etching, and porousness even when sealed were not what was I looking for even though I was already considering less durable stones like soapstone and marble.

Have you done a thorough search here or used google to search the forum? You'll find many threads mentioning PdC, although few are very exhaustive. I'll link one below with some of the best info I've found.

Here is a link that might be useful: Good PdC thread