Identifying obsidian
Volcanic glass tools.
Obsidian is natural volcanic glass, usually black and translucent at thin edges, breaking with very sharp conchoidal fracture. Flow banding and tiny bubbles inside are common and natural.
It knaps like flint but finer, taking an edge sharper than surgical steel — handle every piece as if it were a blade, because it is. Prehistoric blade cores and prismatic blades are distinctive: long, parallel-sided, almost machine-regular.
Because each volcanic source has its own chemistry, obsidian can be traced to a specific volcano — which is why it matters for ancient trade. In regions with no volcanic sources, every piece arrived by exchange or in someone’s pocket, ancient or modern.
Record colour, translucency, and any banding, plus the findspot honestly — for this material above most, where it was found is the story.