Bertrandite with Quartz

specimen number:
2102336

location:
Hayes Ledge Quarry, Greenwood, Maine, USA

description:
Colorless micro crystals of thin platy bertrandite throughout this matrix with colorless crystallized quartz.

The Hayes Ledge quarries, consisting of the adjacent East and West open cuts situated on a prominent ridge in Greenwood, Oxford County, Maine, United States, represent a historic granitic pegmatite locality celebrated for producing distinct crystals of the rare beryllium silicate mineral bertrandite, including well-formed butterfly V-twin crystal aggregations. Geologically, this rugged upland site exposes a highly evolved, zonate lithium-beryllium-bearing granitic pegmatite body hosted within Paleozoic-age metamorphic schists of the Appalachian orogenic belt. During the late-stage cooling of the parent granitic magma, fractional crystallization concentrated highly volatile, beryllium-rich hydrothermal solutions within the core margin, allowing pristine beryl crystals to form, which were subsequently attacked and dissolved by late-stage fluids to reprecipitate bertrandite as lustrous, cream-colored to colorless tabular prisms inside porous albite cleavelandite matrices and pocket collapse breccias. Historically, localized open-cast quarrying at Hayes Ledge began during the early-to-mid twentieth century, primarily targeting industrial-grade feldspar, quartz, and scrap mica for industrial applications, with sporadic activity continuing through the mid-twentieth century until commercial operations for manufacturing feedstocks ceased. Following decades of abandonment, the quarries experienced a dramatic resurgence as a dedicated, specialized specimen mining operation in the early twenty-first century, culminating in a historic August 2017 excavation by legendary field miner Frank Perham and his crew, who breached the massive, eighty-foot-long Mother Mary Pocket.

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