Microcline

specimen number:
2102198

location:
Teller Co., Colorado, USA

description:
An attractive grouping of blocky lustrous bluish green microcline crystals. This is the variety often called amazonite.

The Pikes Peak Batholith in Teller County, Colorado, is arguably the most famous source in the world for the amazonite variety of microcline feldspar. Geologically, these specimens are found within complex granitic pegmatites of the 1.08 billion-year-old Pikes Peak Granite, specifically occurring in miarolitic cavities or pockets. The distinct blue-green color of the amazonite is caused by lead impurities and structural defects within the feldspar lattice that are activated by natural radiation over geologic time. These crystals are frequently found in aesthetic association with dark, smoky quartz, as well as albite and zinnwaldite. Historically, the area has been prospected since the late 1800s, with significant commercial and specimen mining occurring in famous localities like Crystal Peak and the Lake George area. While early miners sought the crystals for museum collections and the gemstone trade, organized specimen mining has continued through the mid-20th century to the present day under various private claims. The region remains a premier destination for mineralogists due to the exceptional size, color, and sharp euhedral form of the crystals recovered from its decomposed granite soils.

Questions about this specimen?
Send an email or call us: 314-341-1811.