This is a giant crystal of microcline, which is the common variety of potassium feldspar. It’s the mineral upon which most of the Maine pegmatite mining industry was based. It was locally known to feldspar miners as “No. 1 Spar,” the highest grade of feldspar.

Location: Albany Rose Quarry, Albany, Oxford County

Gift of Barry J. Heath and Frank C. Perham

Specimen Sponsorship: $7,500

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