Biotite is group of common rock-forming minerals found in igneous and metamorphic rocks. Article by: Hobart M. King, Ph.D., RPG Biotite: Biotite from Bancroft, Ontario, Canada. Specimen is approximately 4 inches (10 centimeters) across. What is Biotite? Biotite is a name used for a large group of black mica minerals that are commonly found in igneous and metamorphic rocks.
MolluscsThe phylum Mollusca is defined by several special characteristics. These defining characteristics include a mantle with a mantle cavity, a shell (except where lost), visceral mass, foot, and radula. The odontophore is in the mouth of most mollusks and it supports the radula (a ribbon of teeth).