Is obsidian igneous rock permeable

Obsidian is an igneous rock that is typically considered impermeable due to its glassy texture and lack of pore spaces. It forms from the rapid cooling of lava, which prevents the formation of crystals, resulting in a dense and solid structure. This characteristic generally limits the ability of fluids to flow through it, making it a poor candidate for permeability. However, in certain conditions, microfractures can develop, potentially allowing limited fluid movement.