This is one of over 4989 textures generated by Filter Forge, a Photoshop plugin that allows you to create your own filters.
With Filter Forge, you can:
Download Filter Forge to use this texture
To open this filter, you must have Filter Forge 3.0 or higher installed on your computer. If you don't have it installed yet, click here to download Filter Forge
Was originally designed to generate obsidian-like textures. After playing with the randomizer and some of the settings I discovered it can be used for just about anything, like what looks like riverbeds, glowing crystals, and more. Possibly my simplest filter yet.
obsidian volcanic glass black purple shiny glossy lava