There are a few houzzers who have, in the past, declared their happiness with leathered granite in absolute black as having a similar look as soapstone. Sorry I can't remember their names, but you might try a search in the discussions for "leathered granite". We have soapstone, so I don't have experience with the alternatives. Here's an informative discussion about the leathering process, with comparisons to honing:
https://www.houzz.com/discussions/what-is-honed-granite-dsvw-vd~630807

One option we always show to clients who want the look of soapstone, we always show them Oscuro Mist. It is a granite, currently we have this stone in a polished and honed finish. Stunning movement and colors, and you get the strength of the granite!

This discussion may interest you - some pros and cons to some of the black granites that you may consider as an alternative to soapstone
http://houzz.com/discussions/637371

A houzz poster named Ann has a leathered quartzite in a dark color that she loves