I am calling this piece a basalt gneiss tablet because it was flat on both sides as shown in the pictures when I found it (like a tablet) and it is a metamorphic basalt gneiss. I polished the front and back faces and left the edges raw to show the beautiful contrast between the original rock and the finished surfaces. Even the rough edges have a shiny look to them which further adds to the allure of this piece.
Rock type: Metamorphic basalt
The banding/layering occurs when a rock experience metamorphic temperatures and pressures and the minerals rearrange into layers as the rock is cooled.
Chemical composition: Gneiss does not have a specific composition, but the layers are typically made up of bands of quartz (SiO2) feldspars and dark minerals such as biotite or hornblende.