Complex sentence: Natural volcanic glass, obsidian will de-vitrify or crystallize over extended periods of geologic time, which can also occur much more quickly in dishwashers due to the chemicals involved in their detergents.
Split into simpler sentences: Natural volcanic glass, obsidian will de-vitrify or crystallize over extended periods of geologic time. Devitrification can also occur much more quickly in dishwashers due to the chemicals involved in their detergents.