I've just found out from Nigel Owen Stoneworkers, who supply the stones for the college, that the black and brown stone I used for my second crow was alabaster after all and not soapstone. They identified it from photos as Cenerino Alabaster from Italy. It certainly felt like alabaster to carve, but I'd expected it to be less opaque when polished, but apparently not all alabaster is transparent. So I guess it's not surprising that I'm finding the black soapstone I'm working on now so different in texture. It's the first soapstone I've used, so I'll see how differently it behaves when carved and if it's possible to carve details clearly as the texture is much more crumbly than alabaster.
I started writing this blog in December 2016, but it covers projects started in spring 2015 onwards, so it was written retrospectively until I caught up with the current term.