Sections
Thumbnails

Tumchaite crystals - click for larger pic
Tumchaite crystals
© Modris Baum

Tumchaite crystals - click for larger pic
Tumchaite crystals
© Modris Baum

Tumchaite crystals - click for larger pic
Tumchaite crystals
© Modris Baum

Search this site

Powered by FreeFind

Home > Mineral Descriptions > Tumchaite - (3 Photos)



Tumchaite
Na2(Zr,Sn)Si4O11 · 2H2O

     Formerly UK 110, tumchaite has been recently described from the Vuoriyarvi alkali-ultrabasic massif in Russia. It seems to exhibit some pleochroism, it is colorless along Y and Z, and greenish-gray along X.

PHYSICAL CHARACTERISTICS:

Color ranges from colourless to pale orange-pink.
Luster is vitreous.
Diaphaneity: transparent to translucent.
Crystal System is monoclinic; P21/c.
Crystal Habits include euhedral platy to tabular crystals forming rosettes
   to 3 mm. Individual crystals average 0.8 mm across and are flattened
   on [010]
Cleavage {100} is perfect.
Fracture is uneven.
Hardness is 4.5
Specific Gravity is approximately 2.78 g/cm3
Streak is white.
Associated Minerals include elpidite, gaidonnayite and quartz.
Distinguishing Features the crystal habit, color and pleochroism.
Origin: Named in 2000 for the Tumcha river near the Vuoriyarvi massif
   in Russia.

CLASSIFICATION:

Dana System
# 70.2.2.2

Strunz Classification
# VIII/F.34-40

REFERENCES:
AmMin 85:1516-1520 (2000)

DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE:

MSH
¤¤¤

PE
¤¤

AP
¤¤

MX
--

SS
--

MC
--

HF
--

BR
--

SX
--

FR
--

Legend