This is a block of steatite (often called Black Pipestone)! This stone will turn nice and black when polished.

This type of stone has been carved into pipes by Native Americans for literally 1000's of years. It holds up exceptionally well to intense heat. Steatite carves the best using a furrier's rasp or other wood carving files. This stone is soft enough that it can be cut quite easily with a regular hacksaw or a bandsaw if you're using a new and sharp woodcutting blade.

Approximate size: 4.5" length x 4" width x 1.5" height (11cm x 10.5cm x 3.8cm)