(typically cabochons) Human Hair Extensions . One variety of obsidian forms with small, white, radially clustered crystals of cristobalite, which result in a very unique black glass with blotchy snowflake patterns. In some Wigs cases, obsidian may also settle with various other impurities which can result in a highly attractive iridescence, often with a gold or Brazilian hair rainbow-like sheen. Obsidian's natural.