Richterite

Richterite is a rare mineral species classified under the group of clinopyroxenes, a subset of pyroxene minerals. It is characterized by its chemical composition of sodium, calcium, aluminum, and silicon, denoted by the formula NaCa2(Mg,Fe,Li)5Si6Al2O22(OH)2. This chemical makeup reflects its presence in nepheline syenite and alkali-carbonate complexes, indicating its affinity for alkaline and peralkaline environments.

The mineral was first discovered in the Hobo Mine, Colorado, USA and was named after Charles Richter, who was a pioneer in earthquake studies. However, Edward S. Dana designated the mineral's name to honor Charles F. Richter in 1914, who was then the assistant in charge of the seismographic service of the California Institute of Technology.

Richterite crystals are typically encountered in a variety of combinations, often occurring in fibrous, acicular, or blocky habits. The coloration may range from brown, gray, or white to a range of green tones, particularly in instances where the iron content is higher. The mineral can be readily identified through its distinctive optical properties, anisotropism, and cleavage patterns.

Given its unique formation requirements, richterite is relatively rare and has only been identified in a limited number of localities worldwide. Despite this, several notable occurrences can be found in the United States, Iceland, and Australia.