Dawsonite with Dolomite

specimen number:
1052517

location:
Mount Amiata, Tuscany, Italy

description:
Colorless acicular crystals of dawsonite across the top of matrix with crystals of dolomite. Good rich example for the species. The specimen comes with a set of previous antique labels as shown at the end of the video. This dates to the very early 20th century.

Dawsonite is a rare sodium aluminum carbonate hydroxide mineral. Geologically, it typically forms in low-temperature hydrothermal environments or as a secondary mineral in alkaline shales and tuffs, most famously occurring within the Green River Formation in the western United States and at Mont Saint-Hilaire in Canada. It crystallizes in the orthorhombic system, appearing as delicate, radiating clusters of acicular (needle-like) or bladed crystals that are usually colorless, white, or pale silver with a vitreous to pearly luster. Historically, the mineral was first described in 1874 from a specimen found on the campus of McGill University in Montreal and was named in honor of the geologist Sir John William Dawson. While not a major ore mineral, dawsonite is of significant interest to geochemists studying carbon sequestration, as it represents a natural way that carbon dioxide can be mineralized and trapped within sedimentary rock sequences over geological time.

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