Purpurite

specimen number:
2102291

location:
B.B. No. 7 Quarry, Norway, Oxford Co., Maine, USA

description:
Masses of purple purpurite throughout matrix.

The B.B. No. 7 Quarry, also known as the Black Mountain No. 7 Quarry, is located in Rumford, Oxford County, Maine, and is situated within one of the most prolific pegmatite districts in the United States. Geologically, the site is a complexly zoned granitic pegmatite belonging to the Oxford County pegmatite field, characterized by an abundance of lithium-bearing minerals and phosphate species hosted within a Devonian-age granite intrusion. The quarry is highly regarded by mineral collectors for its specimens of purpurite, a manganese phosphate mineral that forms as a secondary alteration product of triphylite. These specimens are prized for their intense, velvety purple to reddish-purple color, which results from the oxidation of manganese and typically occurs as dull to earthy masses or satiny crusts on the pegmatite matrix. Historically, mining and quarrying at Black Mountain began in the late 1800s, with various operations targeting mica, feldspar, and later lithium and beryllium. Significant industrial activity occurred during the mid-20th century, particularly during the 1940s and 1950s when the demand for strategic minerals peaked. While large-scale commercial extraction has long since concluded, the B.B. No. 7 remains a classic Maine locality for students of mineralogy and collectors seeking high-quality examples of oxidized phosphate minerals.

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