Other type of Breccia stone: Snakeskin Stone
Grey Algae
Stone Type: Sedimentary Breccia
Grey Algae is a type of Breccia stone. The word Breccia originated from the Italian language which means "loose gravel". Breccia is a clastic sedimentary rock that forms where broken, angular fragments of mineral or older rock debris accumulate and are joined together by smaller particles or bonded by mineral cement.
The cement that binds the clasts in a breccia is generally one of either calcite, silica or iron oxide. The fragments are usually around two millimeters or larger. They commonly form as debris flow deposits along cliffs and underground along faults or where caves collapse and over a long period of time the rocks become cemented together by minerals.
Breccia can come in any color, its color composition is mainly determined by the color of the matrix or cement along with the color of the angular rock fragments.
See material catalog here.