Cosmic Obsidian

Cosmic Obsidian is a trade name for a sheen/rainbow obsidian, natural volcanic glass, whose iridescence appears in swirling, patchy clouds of color against deep black, evoking galaxies, nebulae, or a starry sky. It is closely related to rainbow and aurora obsidian, differing mainly in marketing and the cloud-like distribution of its sheen.

The colors come from aligned nanoscale inclusions and bubble layers that scatter light, not from any pigment. The base material is amorphous glass with conchoidal fracture.

Cutters orient and dome the rough to bring out the 'cosmic' swirls, which makes each polished piece distinctive.

Cosmic Obsidian forms like other sheen obsidian: silica-rich lava chills rapidly into glass, trapping flow-aligned layers of microscopic magnetite crystallites and gas bubbles.

Where these inclusion layers are folded, warped, or unevenly distributed by turbulent lava flow, the resulting iridescence appears as irregular swirls and patches rather than smooth parallel bands, giving the galaxy-like look. Light interference off these layers produces the spectral colors.

The material comes from the same silicic obsidian flows that yield rainbow obsidian, with much marketed material originating in Mexico.

Look for a black glassy stone showing patchy, swirling iridescent color, greens, blues, purples, golds, that shifts as you tilt it under a bright point light, suggesting nebulae or galaxies. Hardness 5-5.5, vitreous luster, conchoidal fracture, white streak.

The sheen is strongest on polished, well-oriented surfaces and fades to plain black at other angles.

Distinguish it from rainbow obsidian (more regular banded sheen), fire obsidian (layered thin-film color), and from goldstone, a man-made glass full of uniform copper sparkles. Cosmic obsidian's natural conchoidal fracture and irregular swirling sheen confirm it is real obsidian.

Cosmic Obsidian is cut into cabochons, spheres, palm stones, and pendants oriented to display the galaxy-like sheen. It polishes to a high gloss; like all glass it can chip, so protective settings are best for wear.

Obsidian has been used since prehistory for sharp blades and mirrors.

Metaphysically, cosmic obsidian is marketed as a stone of protection, exploration, and 'cosmic connection'; these are traditional beliefs rather than established science. Its main appeal is aesthetic, as a striking display and jewelry material.