Hazenite is a hydrous phosphate mineral with chemical formula of , therefore a hydrous alkali magnesium phosphate. It is a member of the struvite

Struvite

Struvite is a phosphate mineral with formula: NH4MgPO4·6H2O. Struvite crystallizes in the orthorhombic system as white to yellowish or brownish-white pyramidal crystals or in platey mica-like forms. It is a soft mineral with Mohs hardness of 1.5 to 2 and has a low specific gravity of 1.7...

 group.

It was first described for an occurrence adjacent to Mono Lake

Mono Lake

Mono Lake is a large, shallow saline lake in Mono County, California, formed at least 760,000 years ago as a terminal lake in a basin that has no outlet to the ocean...

, California

California

California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

, and named after Robert M. Hazen of the Carnegie Institute

Carnegie Institution for Science

The Carnegie Institution for Science is an organization in the United States established to support scientific research....

. It was approved as a new mineral on February 28, 2008 by the Commission on New Minerals of the International Mineralogical Association

International Mineralogical Association

The International Mineralogical Association is an international group of 38 national societies. The goal is to promote the science of mineralogy and to standardize the nomenclature of the 4000 plus known mineral species...

.

It occurs as crystal clusters associated with decomposed algae

Algae

Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...

 remnants on calcite

Calcite

Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate . The other polymorphs are the minerals aragonite and vaterite. Aragonite will change to calcite at 380-470°C, and vaterite is even less stable.-Properties:...

 or aragonite

Aragonite

Aragonite is a carbonate mineral, one of the two common, naturally occurring, crystal forms of calcium carbonate, CaCO3...

. It is precipitated by microbes in the highly-alkaline environment of Mono Lake.