* Formation: Quartzite is formed when sandstone, which is made up of quartz grains, is subjected to intense heat and pressure. This process causes the quartz grains to recrystallize and interlock tightly.
* Result: This recrystallization essentially "erases" the original grain shapes of the sandstone. The result is a dense, hard rock with a very fine-grained texture. You might see some faint remnants of the original grains, but they are often indistinct.
So, while quartzite doesn't have a specific grain shape, it's characterized by its fine-grained texture.
