Do you remember walking along the beach or playing in the sand as a child, when you noticed what seemed little flakes of Gold floating around in the water, and tried to collect them, intending to sell it and get rich.
This has probably happened to everybody at one time or another, including myself. What are these little golden flakes?? This mineral is called Mica.
Mica is actually not a mineral, but a group of minerals, which all (because of their atom structure) are very flaky, to put it simply. AKA, atom structure is that of hexagonal 2D layers, all layered up in the same direction. This makes the mineral very flaky, and pounding water easily separates the loose layers. Really, most of the mica you would find at a beach or lake is the variety Muscovite, which is very common in all types of rock.
Sometimes what will happen is mica flakes, floating around in a lake or ocean, will get buried and compressed in mud or fine sand. With enough pressure, the mud is compressed into a sedimentary rock, and later small chunks of this rock will wash up on the shore, just a plain rock, but if you angle it right, it sparkles beautifully. I’ve found a few of these stones, and they are certainly a wonder to see.
Just as a reminiscent side note, I remember a while back I was asked if I wanted to go along with another family (friends of ours) to go see Gaumer’s jewelry and museum. They had never been there, so I was to show them around. Anyway, they had a little four-year old who’s name was Micha. I told him that there was a stone called Mica, and he got all excited. Every stone we passed, he would ask “Is THAT mica??”. Every time I showed him some: “WHOOOOAAAAA!!”. He was just adorable.