Lazulite

Lazulite is a magnesium aluminum phosphate mineral, MgAl2(PO4)2(OH)2, prized among phosphate collectors for its intense azure-to-indigo color. It forms a series with the iron-rich scorzalite and belongs to the lazulite group, crystallizing in the monoclinic system with a vitreous to resinous luster and a hardness of 5½–6. First described in 1795, its type locality is Freßnitzgraben in Styria, Austria, and it is easily confused with the unrelated lazurite and copper carbonate azurite, though its chemistry and paragenesis are entirely different, typically forming in quartz veins and metamorphic phosphate-iron rocks rather than in metasomatized limestones.

The most celebrated modern occurrence is Rapid Creek, together with nearby Big Fish River and Crosscut Creek in the Dawson Mining District of Yukon, Canada, where crystals form in a Cretaceous ironstone-shale sequence rich in siderite and quartz. Since their discovery in the 1970s, Yukon lazulites have set the world standard for saturated indigo-blue color, sharp doubly-terminated crystals, and mirror-like luster, often twinned and associated with siderite, quartz, augelite, childrenite, gormanite, and apatite; the remote, snowbound terrain and reliance on helicopter-supported expeditions make fine specimens genuinely scarce. In the United States, Graves Mountain in Lincoln County, Georgia is the classic historic locality, yielding well-formed blue crystals embedded in crumbly quartzite matrix, while the Champion Mine in Mono County, California is another noted American source. Austria remains a benchmark European producer, with material from Fischbach and Werfen in Salzburg, including the Höllgraben occurrence at Pfarrwerfen, and Italy contributes specimens from the Vizze Pass in Bolzano and Monte Folgorito near Pietrasanta, Lucca.

Beyond these classic districts, lazulite is also reported from Madagascar, Bolivia, and scattered Alpine localities, usually as smaller, scorzalite-rich, darker crystals, while Brazil's Minas Gerais supplies massive, lapidary-grade material cut into cabochons for jewelry rather than cabinet specimens. Collectors seek lazulite for the rarity of gem-transparent, well-terminated crystals, the striking contrast against white quartz or golden siderite matrix, and its status as a genuinely uncommon phosphate species — Yukon's stock is officially recognized as the territory's gemstone, underscoring the mineral's enduring appeal among systematic and aesthetic mineral collectors alike.