Sodalite Free Foam

Sodalite

Gemstone cherished by the indigenous population of both Americas had been completely overlooked for centuries in the Old World. Luckily, it made scientists pay attention and when they did, they were delighted with its unique qualities. Glowing in ultraviolet and changing its color in sunlight, sodalite is appealing to pundits, gem collectors, and, of course, fashionistas. If you’re looking for a unique gem with unique properties, sodalite fits the bill.

The History and Meaning of Sodalite

The stone’s name consists of two words: soda, which is short for sodium (indeed, this chemical element is part of the mineral) and the Greek ‘lithos’ meaning stone. Sodalite has a few alternative names including alomite and Princess Blue (old trade names for sodalites mined in Canada), afghanite, and hackmanite.

The first mentions of sodalite date back to 1811 when the Scottish chemist Thomas Thomson conducted a series of experiments with a specimen found in Greenland. He established that the gem is a chlorine-containing sodium aluminosilicate. Thomson proposed to classify this mineral as a feldspathoid.

Physicochemical Properties of Sodalite

sodalite is a chlorine-containing sodium aluminosilicate formed in pegmatites and alkaline igneous rocks. Sodalite features a medium hardness of up to 6.0 on the Mohs scale but it is quite fragile. Other distinctive features of the gem are:

– glowing in ultraviolet light – blue stones appear orange when being exposed to UV radiation;

– poor cleavage, which is sometimes seen as cracks in the stone;

– when being polished, the stone acquires either a dull vitreous or waxy luster.

Sodalite is a transparent or translucent mineral featuring a white streak, i.e. it exhibits whitish spots and veins. These patterns are due to the admixture of calcite and albite. When it comes to colors, the most common variety of sodalite is royal blue. In addition, the stone can exhibit various shades of yellow, pink, red, green, and gray.

The most peculiar type of sodalite darkens when being exposed to daylight. This quality can be explained by the sorption properties of the mineral and its ion exchanging abilities. This phenomenon, called tenebrescence, is reversible, so the original color reoccurs in the dark. Crystals that change their color were discovered at the beginning of the 20th century by the Finnish geologist Viktor Hackman. In honor of their discoverer, they were called hackmanites.