This is a student web page project for Mineralogy, a course taught at Emporia State University, Emporia, Kansas, USA.
It was created to provide information on minerals found in Greenland, not meant as the authority on these minerals listed below.
Click for larger image. Image courtesy Perry-Casteneda Library Map Collection (UTexas Online Library). |
Greenland is a mineralogist's dream. There are species of
mineral found in Greenland that occur in very few places around the world.
The geology of Greenland is so diverse due to strange precipitation environments
and igneous intrusions. Four of the rare minerals found in Greenland
will be the focus of this project.
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Aenigmatite is found in the Ilímaussaq igneous intrusion and in some localities in Russia and Trearne Quarry in England (1 ). The Ilímaussaq complex is "beyond any doubt the most mineral-rich area in Greenland" (1, p19). Measuring roughly 8 x 17 km, it is east of the southern town of Narsaq (shown on map above). This intrusion is home to about 200 minerals ( see a partial listing), ten of which are found no where else in the world. Aenigmatite may have been first described from an exported rock sample as early as 1866 (2).
Aenigmatite Technical Data
Chemical Formula: Na2Fe
5TiSi6O
20
Crystal System: triclinic
Cleavage/Fracture: perfect
Habit: lamellar
Hardness: 5-6
Luster: subadamantine, vitreous
Streak: reddish brown
Color: brown, black
Other: may be called cossyrite
Return to Table.
Ikaite is a mineral that is formed in the cold marine waters of a fjord. It is sometimes referred to as a pseudo-calcite or aragonite, but can crystallize in waters too cold to support either. It will actually destabilize and decompose into calcite if the water temperature climbs above 8 degrees Celsius! It is found in the Ika Fjord, from which it is named.
Ikaite Technical Data
Chemical Formula: CaCO3·6(H
2O)
Crystal System: monoclinic
Cleavage/Fracture: none
Habit: stalagtitic or tabular
Hardness: unknown (perhaps that of calcite ~3)
Luster: earthy
Streak: white
Color: white
Image from Adam's Minerals-- is this really ikaite? If the mineral is not stable at room temperature, then this is probably just a mineral that has a habit and texture that is close to some forms of ikaite.
Visit the ikaite home page for images and information.
Return to Table.
This is one of the ten minerals unique only to Greenland's Ilímaussaq intrusion (See above for details) and is also completely unique to this complex. Semenovite has only been found on one spot on the Ilímaussaq intrusion (Taseq), and had to be re-discovered in 1988 after the exact locality had been forgotten. It was originally discovered in 1968 (2).
Semenovite Technical Data
Chemical Formula: (Ca,Ce,La,Na)10-12
(Fe2+,Mn)(Si,Be)20
(O,OH,F)48
Crystal System: orthorhombic
Cleavage/Fracture: none
Habit: intricately twinned crystals form tetragonal dipyramid shape,
largest crystals found ~1cm
Hardness: 3.5-4
Luster: vitreous
Streak: white
Color: brown (when fresh), orange-brown, gray
Other: found on epididymite, in cavities and fractures in the intrusion
Want to see Semenovite?
Try Webmineral's image. The picture is not the best, but those crystals
are small!
Return to Table.
Tugtupite is not unique to Greenland. It is very rare though, being found in small amounts in the Kola Peninsula of Russia and in Quebec, Canada. It was first discovered in Tugtup (from which it gets its name) in 1957 in the Ilímaussaq intrusion (see above for explanation ). Tugtupite is only found in hydrothermal veins, and is often in a massive habit. Gem quality tugtupite is the red shades found only in Greenland. Tugtupite gems are nearly always in cabochon because of massive habit and are prized for their highly active fluorescence ( 2).
Tugtupite Technical Data
Chemical Formula: Na4AlBeSi
4O12Cl
Crystal System: tetragonal
Cleavage/Fracture: cleaves imperfectly in a dipyramid, fractures conchoidally
(3)
Habit: massive
Hardness: 4
Luster: vitreous
Streak: white
Color: white, pink, red (light blue recently discovered)
Other: fluorescent mineral, darkens towards red even in normal sunlight.
Color fades when kept in a dark place (2).
For pictures and further information on this mineral, visit Jewel-Stones of Greenland's Tugtupite page.
Return to Table.
(1)MinDat. "Aenigmatite." http://www.mindat.org/show.php?name=Aenigmatite Accessed 4-2-01.
(2)Petersen, O.V. and Secher, K. The Minerals of Greenland. Mineralogical Record, v. 24.2 March-April 1993.
(3)Jewel-Stones of Greenland. "Tugtupit." http://www.minershop.com/greenland/Shop_Online/Tugtupit_detail/tugtupit_detail.html Accessed: 3-20-01.
Perry-Castaneda Library Map Collection, University of Texas Online Library. "Greenland Small Map." http://www.lib.utexas.edu/Libs/PCL/Map_collection/cia00/Greenland_sm00.jpg Accessed: 4-10-01.
For technical data:
WebMineral. "Aenigmatite Mineral Data." http://webmineral.com/data/Aenigmatite.shtml
Accessed: 3-4-01.
--. "Ikaite Mineral Data." http://www.webmineral.com/data/Ikaite.shtml
Accessed: 3-4-01.
--. "Semenovite Mineral Data." http://webmineral.com/data/Semenovite.shtml
Accessed: 3-4-01.
--. "Tugtupite Mineral Data." http://www.webmineral.com/data/Tugtupite.shtml
Accessed: 3-4-01.
Links of Interest:
Adam's Minerals, http://www.adamsminerals.com
Mineral & Gemstone Kingdom, http://minerals.net/
Mineralogy Database, http://webmineral.com
Rare Minerals, http://www.rareminerals.com
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Created April 12, 2001
email: flaxlian@hotmail.com
copyright 2001 © Lianne Flax All rights reserved.
