Tugtupite

Tugtupite (also Berylliumsodalith or reindeer stone) is a rarely occurring mineral from the mineral class of silicates ( and Germanates ). It crystallizes in the tetragonal crystal system with the chemical composition Na4 [( Cl, S) | BeAlSi4O12 ] and usually develops granular to massive, shiny glass and translucent mineral aggregates to about 10 cm in size, rarely crystals in the millimeter range.

Special Features

In the sunlight, the color spectrum of Tugtupite ranges from white through pink to deep red Very rarely, bluish stones are found. The red color is due to small amounts of sulfur in Tugtupite. If a pale Tugtupite is exposed to UV light or sunlight, the red color reinforces This depression can last for weeks. In the darkness, the red fades again ( photochromism ). Tugtupite can also respond to heat.

Tugtupite is known for its excellent fluorescence. When exposed to UV light or sunlight, the red reinforced under short-wave UV light it glows cherry red, more or less under long-wave UV light strongly orange. Dark Red Tugtupite from the Kvanefjeld area shows the strongest response to UV light, the color deepening mode for a few weeks. This Tugtupite shows no phosphorescence. Pale Pink Tugtupite from the Taseq area shows another UV reaction: a weaker red under short-wave UV, salmon - orange under long-wave UV and pink- purple under mid-wave UV. This Tugtupite shows a strong, whitish phosphorescence. Again react differently stones from other areas in the Fund Ilímaussaq complex is a pink-orange under short-wave UV, a very bright white under mid-wave UV and orange under long-wave UV, thereby also phosphorescent.

Specifying the Mohs is specified according to sources with 4 or 5.5 to 6.

Etymology and history

European geologists discovered Tugtupite in 1957. The Greenland Inuit knew this stone, however, for centuries. They named Tugtupite for the blood of reindeer ( " tuttu "). His official name was given to the mineral, however, in 1962 by its first describer H. Sørensen, who named it after its type locality Tugtup Agtakorfia ( Tuttup Attakoorfia ).

Classification

In the old ( 8th edition ) and the new classification of minerals ( 9th Edition ) by Strunz the Tugtupite belongs to the Department of framework silicates ( tectosilicates ). This department has been divided since the Strunz'schen Mineral classification reissue on and partially redefined, so that the mineral now in the department and sub-department " framework silicates ( tectosilicates ) without zeolitic H 2 O - with other anions " is.

The classification of minerals according to Dana sorted the Tugtupite in the department " tectosilicates Al -Si Framework feldspathoids and related species" (Translated: k with Al -Si framework, Foidite and relatives ).

Education and Locations

Tugtupite is likely to form in hydrothermal veins of syenite pegmatites, where it replaces the Chkalovite. The occurrence is limited to an 8 x 17 km large area in the south of Greenland, the " Ilímaussaq complex". There you will find more than 250 different minerals ( Greenland: more than 500 minerals, with 77 Type localities ). Here is the first Tugtupite in 1957 found: in Tugtup Agtakôrfia, on the northern shore of Tunuljarfik fjord, which cuts through this nepheline syenite intrusion. The small town of Narsaq located 11 km west of the center of Ilímaussaq complex. The area is only sparsely covered with low plants, very weathered and increases from SE to NW at. Mount Ilímaussaq ( 1390 m) is the highest point of the complex. The lost area can only be reached on foot in the summer months.

Tugtupite is found also in Mont -Saint -Hilaire (Quebec, Canada) and in the Lovozero massif on the Kola Peninsula in northern Russia. The U.S. Geological Survey reported that large quantities Tugtupite have been found in rivers of Nepal.

Crystal structure

Tugtupite crystallizes in the tetragonal crystal system in the space group, the lattice parameters a = 8.640 Å and c = 8.873 Å and two formula units per unit cell.

Use as a gemstone

Translucent or transparent, deep red ( in daylight ) Stones from the region Kvanefjeld become precious stones processed ( rings, pendants, etc.). Inuit artists to improve their income by grinding the raw stones, polish and then sell. Good Tugtupite are relatively translucent and without any other visible inclusions of foreign minerals. The best stones are almost transparent, bright red and very sought after by gemstone enthusiasts. However, one must take into account the low Mohs hardness. Tugtupite should therefore not be used in everyday used rings. Only Greenland can supply the international market with sufficient quantities of valuable, sometimes deep red and very sought Tugtupits.