Home > Mexico II Type Locales – December 22 > MS1703 Boleite

Boleite - Sold


Boleite is chemically complex: potassium lead silver copper chloride hydroxide. Mallard & Cumenge (1891) named boleite for its original occurrence at Boleo. More than a century later, Cooper & Hawthorne (2000) established the currently accepted formula for boleite after finding essential potassium and also showing an absence of molecular water. Following its original description in 1891, mineralogists debated the identities of boleite and its similarly appearing associates pseudoboleite and cumengeite. Friedel (1906) made thin sections of the complex intergrowths, showing optically that they consisted of different sections, and that pseudoboleite and cumengeite form epitaxially on cubic boleite. How many fine cumengeite stars fell to Friedel's blade?

This is a single crystal of boleite. This example has roughly equal development of both cube {100}, octahedron {111} forms, making it a regular cuboctahedron. This specimen is free of matrix, typical of boleite recovered from moist clay at this unique locality.