Soapstones coming from Greenland or Africa are relatively soft. You can easily saw or carve in these stones. It is nearly impossible to guess the colours in the stones until the final polishing. It is easy to polish the stones totally smoth.
After application of beeswax often beatifull and totally unexpected colouring will appear on the surfaces.
Stones of moler are another and exiting material to work with. For centuries it has been used in the industry to produce brigs with an extremely isolating effect. In Denmark big graves are found on the islands of Fur and Mors in the western part of Jutland. In the clay several sceletons of insects, fish, mussels and scallops are often found and now presented in the museums beside the factories.
Burnt moler is very soft in the structure. You can saw and cut in it with a knife and form the sculptures or reliefs, you want. But take care : The stones are very fragile.The biggist stones, I have worked with, have size 25 x 25 x 50 cm.
After production it will be possible to cast the sculptures or reliefs in bronze. Expensive, but often with unexpected surfaces and beatifull details.