Phlogopite Wikipedia
Phlogopite is a yellow, greenish, or reddishbrown member of the mica family of is also known as magnesium mica.. Phlogopite is the magnesium endmember of the biotite solid solution series, with the chemical formula KMg 3 AlSi 3 O 10 (F,OH) substitutes for magnesium in variable amounts leading to the more common biotite with higher iron content.