Page 2

Volume 2 Issue 3

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 article.

Aenigmatite is found in the Ilímaussaq igneous intrusion and in some localities in Russia and Trearne Quarry
in England .  The Ilímaussaq complex is "beyond any doubt the most mineral-rich area in Greenland".  Measuring roughly 8 x 17 km, it is east of the southern town of Narsaq.  This intrusion is home to about 200 minerals, 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.
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.
Semenovite is one of the ten minerals unique only to Greenland's  Ilímaussaq intrusion 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.
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.  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.

Ikaite Technical Data
Chemical Formula: CaCO₃·6(H₂O)
Crystal System: monoclinic
Cleavage/Fracture: none
Habit: stalagtitic or tabular
Hardness: unknown (perhaps that of calcite ~3)
Luster: earthy
Streak: white
Color: white

Aenigmatite Technical Data
Chemical Formula: Na₂Fe₅TiSi₆O₂₀
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

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

Tugtupite Technical Data
Chemical Formula: Na₄AlBeSi₄O₁₂Cl
Crystal System: tetragonal
Cleavage/Fracture: cleaves imperfectly in a dipyramid, fractures conchoidally.
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.