When in contact with groundwater, this rock will absorb the water which bleaches the rock white and expands it in size to create the mineral (*) perlite.
The diffusion of water into materials made from this rock creates a narrow band with a width that grows like the square root of time and thus allows the age of such materials to be found in a namesake hydration dating. When in contact with groundwater, this rock will absorb the water which bleaches the rock white and expands it in size to create the mineral (*) perlite. Â Patches of crystals of cristobalite can form during cooling resulting in white blotches which give rise to the "snowflake" variety of this rock. The high silica content is derived from its formation from polymerized lava whose viscosity generally prevents any crystals from forming during cooling. Its keenness makes it ideal for the construction of medical blades. For 10 points, identify this extrusive igneous rock, a glossy black volcanic glass.
The diffusion of water into materials made from this rock creates a narrow band with a width that grows like the square root of time and thus allows the age of such materials to be found in a namesake hydration dating.
obsidian