This extensive flat brings together numerous specimens with Philipsbornite and Osarizawaite crystals from the famous Grandview Mine in the Grand Canyon, accompanied by additional secondary copper minerals. The specimens mainly show crusty, fine-grained to granular aggregates in typical yellow, green, and turquoise colors, locally accompanied by bluish or brownish areas. Individual crystals can be locally recognized but usually occur as tightly intergrown coatings, which is characteristic for this mineral group. Overall, the flat offers an exceptional range of color, texture, and mineral associations within a single collection.
Geology & Origin
The Grandview Mine is a classic locality for rare secondary copper minerals formed in the oxidation zone of copper rich ore veins. Philipsbornite and Osarizawaite develop here as arsenates under oxidizing conditions and are commonly found in close paragenesis with other copper and lead arsenates. These complex formation processes account for the wide morphological and color diversity of the specimens and make such flats especially valuable for systematic collections and comparative paragenetic studies.