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Tugtupite
Current inventory:  3 gems
 

Chemistry:  Na₄AlBeSi₄O₁₂Cl

Discovered in 1957;   IMA status: Valid (IMA approved 1962).
Tugtupite is named after its discovery locality, Tugtup agtakôrfia, Tunugdliarfik, Greenland.

Classification

Mineral Classification:

Silicates

Strunz 8th Ed. ID:

8/J.11-50

8 : Silicates
J : Tectosilicates (network) without anions unfamiliar to the tetraheders
11 : Sodalite group, Tsaregorodtsevite - Wadalite series

Crystal Data

Crystallography:

Tetragonal - Disphenoidal

Crystal Habit:

Crystals are short tetragonal prisms with pyramids, sphenoids, and bisphenoids, to 3 mm; fine-grained aggregates, massive.

Twinning:

Penetration twinning produces pseudocubic triplets; pseudotrigonal contact twins with composition planes.

Physical Properties

Cleavage:

[101] Distinct, [110] Fair

Fracture:

Conchoidal

Tenacity:

Brittle

Hardness (Mohs):

4.0

Density:

2.33 (g/cm³)

Luminescence:

Fluorescent; bright orange under LW UV. Phosphorescent red to rose-pink under UV; photochromic, pale colors become deep pink on exposure to sunlight or X-rays.

Radioactivity:

Not Radioactive

Other:

Piezoelectric

Optical Properties

Color:

White, Pink, Crimson, Blue, Green

Transparency:

Opaque, Translucent, Transparent

Luster:

Vitreous to Greasy

Refractive Index:

1.492 - 1.502  Uniaxial ( + ); anomalously Biaxial

Birefringence:

0.0060

Dispersion:

0.012

Pleochroism:

Weak Lilac to weak Red-Orange

Occurances

Geological Setting:

Replaces chkalovite in hydrothermal veins cutting sodalite syenite and syenite (Ilimaussaq intrusion, Greenland); an alteration product in pegmatites in a differentiated alkalic massif (Lovozero massif, Russia).

Type Locality:

Tugtup agtakôrfia, Ilimaussaq complex, Narsaq, Kitaa (West Greenland) Province, Greenland

Year Discovered:

1957

View mineral photos:

Tugtupite Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Tugtupite is a member of the Sodalite group that also includes Hackmanite, Haüyne and Lazurite. Tugtupite was discovered in Tugtup agtakôrfia, Tunugdliarfik, Greenland in 1962. It is also known as Reindeer Stone because Tugtup means reindeer. Most material is opaque to translucent and used for cabochons. Transparent material is rarely available and cut into very small faceted gems. These are very rare and usually slightly to moderately included. Tugtupite has an unusual characteristic in that it darkens in color when exposed to UV light and then slowly lightens back up.

The main sources of Tugtupite are Tasseq Slope, Ilimaussaq complex, Narsaq, Kitaa Province, Greenland; and minor occurances at Kola Peninsula Russia and Mont Saint-Hilaire, Quebec, Canada.
 

  
Tugtupite gems for sale: