Slate.
With a sharp rock cit slow then twist the bone off the knuckle.
Yes, slithers of which, when broken from a bigger lump (known as 'knapping') have sharp cutting edges.
Obsidian. It has very fine grain or is amorphous, and it has a conchoid fracture, so it can be worked to a sharp edge and point. Gabbro, on the other hand, has a very coarse grain and it difficult to get and edge or point on at all.
A path along the crest is easily followed across the first tor of broken rock.
The definition of a shard is a piece of broken ceramic, metal, glass, or rock, typically having sharp edges. So with that definition, I would say that a shard of wood just means a piece of broken wood having sharp edges. If you are referring to the crossword puzzle hint, the answer is splinter.
You are a "promise." Promises can be strong and enduring, much like a rock, but they can be easily broken or hurt by a single word or action, leading to disappointment or betrayal.
Be careful, that knife is sharp. Don't step on that sharp rock!
The shape of a rock that has just been broken off is usually irregular and angular, with rough edges where the break occurred. This is due to the fracturing process that creates jagged surfaces on the newly exposed areas of the rock.
a sharp hard rock
The surface of a broken rock layer, often referred to as a joint or fracture surface, displays irregularities and sharp edges resulting from the rock's physical or chemical weathering processes. These surfaces can exhibit various textures and patterns, influenced by the rock's mineral composition and the conditions under which it fractured. Such surfaces are crucial in geological studies as they can provide insights into the history of tectonic activity, erosion, and sedimentation in an area.
Any rock can be broken up and later form a sedimentary rock.
gravel sand talus detritus broken up rock?