The word Mariposite is often used to identify green micas colored by small amounts of chromium. Mariposite is also used to name a group of green and white metamorphic rocks with high mica content. It is interesting to know that the term “Mariposite” has been used interchangeably in different contexts since the 1800s. Moreover, mariposite is not the name of any formally recognized mineral. It is informally used to define various green-colored micas.
The name itself originates from the Mariposa community in California. Green mica and rocks are commonly seen in this area. Many prospectors hunted for mariposite during the California Gold Rush to find gold.
Mariposite is made up of small amounts of green mica with major constituents: quartz, calcite, dolomite, barite, or ankerite.
The rock forms when another rock, serpentinite (derived from the earth’s mantle), is altered under mineral-laden hot water. The temperature may go up to 650F. The hot fluids travel upwards and along faults, fissures, and fractures, and react with serpentinite. As a result, deposits of quartz, chromium-rich mica, gold, and sulfides are formed.
Mariposite Mineral Reserves
Mariposite mineral is found worldwide. The notable localities in the US are Nevada, Tennessee, Utah, Washington, Alaska, Arizona, California, and Colorado.
Austria, Japan, China, Canada, Ireland, France, Spain, Sweden, Venezuela, and Papua New Guinea also have big reserves.
Mariposite is a popular landscaping stone. It is also used as a veneer on the wall. Some specimens are polished for jewelry making.
It is also important a gold ore and a source of gold placer. Mariposite is cut to make dimension stones for cemetery markers, fireplaces, and facing stones. It is commonly used where strength and weather resistance is not required. Mariposite turns to muddy brown color when exposed to rain.
Mariposite is also used in the lapidary industry. However, only solid pieces with high quartz percentage must be used for lapidary.