1. obsidian - Noun
2. obsidian - Adjective
A kind of glass produced by volcanoes. It is usually of a black color, and opaque, except in thin splinters.
Source: Webster's dictionaryReligion is a barbarous obsidian knife poised over our chests - put it in a cabinet and admire it as a work of art, but don't ever wield the damned thing ever again. PZ Myers
When Barrons looks at me like that, it rattles me. Lust, in those ancient, obsidian eyes, offers no trace of humanity. Doesn't even bother trying. Savage Mac wants to invite it to come out and play. I think she's nuts. Nuts, I tell you. Karen Marie Moning
Eyes as black and as shiny as chips of obsidian stared back into his. They were eyes like black holes, letting nothing out, not even information. Neil Gaiman
Elsewhere, Andrea reveals Obsidian Platinum and after her speech, the school's mascot - Toyman in disguise as a tiger similar to what Nia saw - attacks. Source: Internet
An opal doublet consists of a relatively thin layer of precious opal, backed by a layer of dark-colored material, most commonly ironstone, dark or black common opal (potch), onyx, or obsidian. Source: Internet
However, over the years fans have come to accept Obsidian Entertainment's follow up as not only being part of the 'main' series, but perhaps the best instalment in the entire franchise. Source: Internet