Pyrite

Description

Pyrite (iron disulphide, FeS₂) is one of the most widely recognised minerals in the world — “Fool’s Gold” — yet fine crystallised specimens are anything but common. The cubic crystals from Hohenems, Vorarlberg, Austria, are prized for their sharp geometric faces, bright metallic lustre and the characteristic pyritohedral or cubo-octahedral habit that makes them immediately recognisable as classic pyrite.

Pyrite forms across a wide range of geological settings — from hydrothermal veins to sedimentary iron formations — and the Alpine and sub-Alpine deposits of Austria have yielded collector-quality pyrite crystals since the 18th century. Well-crystallised specimens with undamaged faces and natural matrix are increasingly rare and appreciated by both European and international collectors.

Well-crystallised pyrite is distinguished by its combination of brass-yellow metallic colour, high specific gravity (5.0), and the characteristic striated faces — fine parallel lines on cubic faces at right angles to those on adjacent faces — a feature diagnostic of the species. Natural pyrite oxidises slowly on exposed surfaces, converting over time to limonite; specimens stored in stable, low-humidity environments retain their original metallic brilliance indefinitely. Collector-grade pyrite is assessed on crystal perfection, face lustre, habit variety, and quality of matrix: naturally matrix-mounted crystals are considerably more valuable than loose single crystals.