Top Customer Reviews. Failure of an off-side windshield wiper blade resulted in an arc of light scratches on the glass of my concours-winning collector car. Ranging from almost-undetectable to 'can just feel them under my fingernail' the scratches caught the light and weren't going to pass muster at my next car show.
An obsidian rock is an extrusive igneous rock that forms when a volcano erupts and has no time to crystallize, so it has a glassy texture. Obsidian rocks are generally black i â¦ n color.o rock is completely impermeable, but some porous rocks like shale and pumice are mostly impermeable, because â¦ the pores are not interconnected, thus not allowing fluids or gases to pass through them. This is why shale makes a good cap-rock, and pumice floats instead of sinking. 2 people found this useful.
About Snowflake Obsidian. Snowflake Obsidian is both an igneous rock and a natural glass. This rock-glass is formed when lava cools with incredible rapidity and minimum crystallization. When this occurs, the lava gradually transforms into a black glass.nowflake Obsidian is both an igneous rock and a natural glass. This rock-glass is formed when lava cools with incredible rapidity and minimum crystallization.