phlogopite

Table of Contents

Introduction References & Edit History Quick Facts & Related Topics

Images

Read Next

solar eclipse, sun, moon, astronomy, space

How Do You Tell the Difference Between Total, Annular, Solar, and Lunar Eclipses?

Arrangement of the phases of the moon in total eclipse with Blood Moon

9 Celestial Omens

Solar system illustration. (planets; sun)

Why Are Planets Round?

Spiral Galaxy type Sa-Sb or Sa/Sb in the constellation Virgo. The majestic Sombrero Galaxy Messier 104 (M104) or NGC 4594. The team took six pictures of the galaxy, stitched them together to create the final composite image. Photo from May-June 2003

9 Britannica Articles That Explain the Meaning of Life

Solar System with the sun and planets amid stars. Illustration Venus Mercury Earth Mars Jupiter Saturn Neptune Uranus space orbit

Understanding Kepler’s Laws of Planetary Motion

Discover

Four year old boy with grandfather and father lighting Hanukkah menorah. Photo taken on: December 21st, 2009

Which Is Correct: Hanukkah or Chanukah?

Facsimile of one of William Henry Ireland's forgeries, a primitive self-portrait of William Shakespeare(tinted engraving). Published for Samuel Ireland, Norfolk Street, Strand, December 1, 1795. (W.H. Ireland, forgery)

The Time a Law Clerk Successfully Forged a New Shakespeare Play to Impress His Dad

9 of the World’s Deadliest Snakes

The impeachment trial of Pres. Andrew Johnson, illustration from Frank Leslie's Illustrated Newspaper, March 28, 1868.

What If the President Is Impeached?

Nativity Scene, Adoration of the Magi, Church of the Birth of the Virgin Mary, Montenegro

Why Is Christmas in December?

Indian hijras participate in a religious procession in Gandhinagar, India, some 30 kilometers from Ahmedabad, on March 22, 2017. Hijra is a term used in South Asia which refers to transgender individuals who are born male. (gender identity, gender expression)

6 Cultures That Recognize More than Two Genders

Town of Sisimiut located on the coast of the Davis Strait on Kangerluarsunnguaq Bay, Greenland

The Largest Islands in the World

phlogopite

mineral

Also known as: brown mica

Written and fact-checked by The Editors of Encyclopaedia Britannica

Article History

Also called:: brown mica

Related Topics:: mica

See all related content

phlogopite, basic aluminosilicate of potassium, magnesium, and iron that is a member of the common mica group. Varieties that contain only small amounts of iron are economically important as electrical insulators. Phlogopite occurs typically as a metamorphic product (e.g., in crystalline metamorphosed limestones) and also in ultramafic igneous rocks. Phlogopite forms a chemical substitution series with biotite, from which it is arbitrarily distinguished by a magnesium-to-iron ratio greater than 2:1. For detailed physical properties, see mica (table).

The name phlogopite also denotes an iron-free compound regarded as making up a large part of the mineral. Its chemical composition is K₂Mg₆(Si₆Al₂O₂₀)(OH)₄.

This article was most recently revised and updated by John P. Rafferty.