Assertion: obsidian | /r/HasProperty | hard
Facets:
Source sentences:
text: Obsidian is hard, brittle, and amorphous; it therefore fractures with sharp edges.
text: Obsidian is one of the hardest blocks to destroy in Minecraft .
text: The mask itself could be made of green or black stone, wood, obsidian (a hard dark volcanic glass/stone), or even placed on a real human skull.
text: Obsidian, naturally occurring volcanic glass, is smooth, hard, and far sharper than a surgical scalpel when fractured, making it a highly desired raw material for crafting stone tools for most of human history.
text: Obsidian, naturally occurring volcanic glass, is smooth, hard, and far sharper than a surgical scalpel when fractured, making it a highly desired raw material for crafting stone tools for most of human history.
text: Obsidian is hard and brittle and that is why it fractures with very sharp edges.