Sometimes, yes, lava rock can be shiny. This shininess is due to a thin, glassy rind that forms on the surface of the lava when it cools rapidly.
Here's a breakdown:
- Rapid Cooling: When molten lava encounters air or water, the sudden temperature drop doesn't allow minerals to crystallize properly.
- Glassy Rind Formation: This rapid cooling results in a thin layer of volcanic glass forming on the surface.
- Iridescence: This glass layer often possesses an iridescent luster, giving the rock a shiny appearance.
Not all lava rock is shiny. The presence of a shiny surface depends on the cooling conditions. Slower cooling allows for mineral crystal formation, which typically results in a more matte or dull finish.
In short, some lava rock exhibits a shiny, iridescent surface due to the formation of a glassy rind from rapid cooling.
