Home > Laskowski Ⅰ – June 22 > MS1809 Boracite


Boracite is a magnesium borate chloride. Werner (1789) named the mineral for its boron content. Boracite crystals show cubic crystal forms, but are actually orthorhombic at room temperature. On heating boracite to 265°C, Mallard (1883) showed that boracite assumes cubic symmetry. Such thermal inversions are the most precise geo-thermometers; these crystals presumably form above 265°C. This is a nice example of a gemmy 3 mm crystal in anhydrite matrix. The crystal shows a rather equal development of cubic, octahedral and dodecahedral forms. It has 6 + 8 + 12 = 26 faces.

From the collection of E.R. Laskowski (1949-2020). Laskowski acquired this specimen in 2006; labels from Laskowski and another dealer accompany the specimen.

Price: $100

Item code: MS1809

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