St Peters Dome, Cheyenne District (St. Peters Dome District), El Paso Co., Colorado, USA
Cabinet, 10.3 x 8.0 x 6.0 cm
Lustrous, diverging, metallic foil-like, golden-bronze astrophyllite blades are richly and superbly set in cabinet-sized pegmatite matrix from this well-known Colorado locality - St. Peters Dome. Astrophyllite is a rare potassium, sodium, iron, manganese, titanium silicate and these are large, up to 6.0 cm, crystals of the species and for the locality. The collection this came out of was a museum stash dating to prior to World War I.