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Smithsonian National Museum of Natural History

Tugtupite

Crown view of tugtipite gem (NMNH G11670)
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SpecimenCatalog NumberLocalityWeight
TugtupiteNMNH G11671-00Greenland-
TugtupiteNMNH G11670-00Greenland3.2 ct

Gift of Smithsonian Gem and Mineral Collectors in 2018.

Tugtupite was first discovered in 1957, at Tugtup agtakôrfia, Greenland, a few kilometers to the east of the town of Narssaq, by Professor Henning Sørensen. The name tugtupite is derived from the locality where the mineral was first found.  Tugtupite is also referred to as Tuktu, a named derived from the Greenlandic Inuit word for reindeer (tuttu) and means “reindeer blood.” Tugtupite is a rare silicate, closely related to sodalite. The red variety of the mineral tugtupite has been used as a gemstone since 1965. It is typically massive in nature, however, small prismatic crystals that are transparent have been found growing on cavity walls in massive tugtupite.

Tugtupite has a Mohs hardness of 6 ½ and a vitreous luster.Tugtupite exhibits a variety of fascinating optical properties, including tenebrescence, fluorescence, and phosphorescence. Tenebrescence is the ability of minerals to change or darken in color when exposed to light. Tugtupite is strongly tenebrescent with colors changing from white or light pink, to vivid red and even purple-red. The color changes quickly, within minutes, when exposed to sunlight or short-wave ultraviolet light. Absence of daylight during the long arctic winter causes tugtupite to naturally lose its color over weeks to months, returning to white or very light pink. This color-change is reversible, as tugtupite will again regain its red color when re-exposed to sunlight. Tugtupite is also strongly fluorescent in both shortwave (SWUV) and long-wave (LWUV) ultraviolet light. Under SWUV light, it glows strongly orange to orangey-red; whereas under LWUV light, it glows weakly salmon-pink. It is sometimes referred to as the “King of Fluorescent Minerals.” Tugtupite is also phosphorescent, with the color fading from a light to dark-green after a few minutes once an UV light source has been extinguished.
The opaque to translucent tugtupite historically mined is typically cut into cabochons or made into beads. The recently discovered semi-transparent to transparent tugtupite has quickly gained popularity as an extremely rare and unusual faceted gemstone because of its attractive raspberry-red color and intriguing luminescence properties. Although tugtupite has been found in Russia and Canada, gem-quality tugtupite is only found in Greenland. The Smithsonian acquired a 3.20ct round brilliant cut gem, faceted by Mr. Lars Schou, and two “ulu” silver pendants with tugtupite cabochons (ulu is an all-purpose knife traditionally used by Inuit, Yupik, and Aleut women), designed and created by Mike Møller. These are the first tugtupite gems acquired for the National Gem Collection.


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