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Nambulite
Current inventory:  1 gem
 

Chemistry:  (Li;Na)Mn²⁺Si₁₀O₂₈(OH)₂

Discovered in 1972;   IMA status: Approved
Nambulite is named after Professor Matsuo Nambu (1917 -) of Tohoko University, Japan, for his studies of manganese minerals.

Classification

Mineral Classification:

Silicates

Strunz 8th Ed. ID:

8/F.27-50

8 : Silicates
F : Inosilicates (chain and band) double chains [Si2O6]4-
27 : Rhodonite - Inesite series

Crystal Data

Crystallography:

Triclinic - Pinacoidal

Crystal Habit:

Crystals are prismatic to tabular crystals, to 8 mm; massive in veinlets.

Physical Properties

Cleavage:

[001] Perfect, [100] Distinct, [010] Distinct

Fracture:

n/a

Tenacity:

Brittle

Moh's Hardness:

6.5

Density:

3.51 (g/cm³)

Radioactivity:

Not Radioactive

Optical Properties

Color:

Reddish brown, orange-brown, reddish orange

Transparency:

Transparent, Translucent to Opaque

Luster:

Vitreous

Refractive Index:

1.707 - 1.730  Biaxial (+)

Birefringence:

0.023

Dispersion:

Weak

Pleochroism:

Slight

Occurances

Geological Setting:

In veinlets cutting braunite ores in chert (Funakozawa mine, Japan).

Type Locality:

Funakozawa mine, Kitakami Mts, Iwate Prefecture, Tohoku Region, Honshu Island, Japan

Year Discovered:

1972

View mineral photos:

Nambulite Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Nambulite is a very rare mineral first found at the Funakozawa Mine in the Kitakami Mountains of Japan and more recently found at the Kombat Mine near Tsumeb, Namibia. Most Nambulite is opaque, occasionally translucent, very rarely transparent and only available as cabochons. There is a completely transparent, flawless crystal reported from the Namibian material but this is in a private mineral collection and not available for faceting. If there were any transparent, faceted gems, they would be extremely rare and very valuable. Nambulite has a very beautiful, very intense orange-red color.
 

  
Nambulite gems for sale: