Fluornatromicrolite can be an mineral that is extremely uncommon gem that is reasonably new. It was approved by the IMA in 1998. Fluornatromicrolite differs in color from yellowish orange to green that is deep. It was first discovered at the Quixaba pegmatite, Paraiba, Northeast Region, Brazil. Crystals available at Alto Ligonha District, Zambezia Province, Mozambique are typically green that is deep rarely transparent enough for faceting.

The few sourced elements of Fluornatromicrolite are: Paprok, Nuristan Province (Nurestan; Nooristan), Afghanistan; Quixaba pegmatite, Quixaba, Frei Martinho, Borborema mineral province, Paraíba, Northeast Region, Brazil; Alto Ligonha pegmatites, Alto Ligonha District, Zambezia Province, Mozambique; Shigar Valley, Skardu District, Baltistan, Northern Areas, Pakistan; Mokrusha Mine, Alabashka field that is pegmatite Yuzhakovo Village, Ekaterinburgskaya (Sverdlovskaya) Oblast’, Middle Urals, Urals area, Russia.   

Chemical Formula: (Na,Ca,Bi)2Ta2O6F
Sodium Calcium Bismuth Tantalum Fluorine Oxide
Molecular Weight: 570.32 gm
Composition: Sodium 4.84 % Na 6.52 % Na2O
Calcium 4.22 % Ca 5.90 % CaO
Tantalum 63.45 % Ta 77.48 % Ta2O5
Bismuth 7.33 % Bi 8.17 % Bi2O3
Oxygen 16.83 % O
Fluorine 3.33 % F 3.33 % F
  % F -1.40 %  -O=F2
  100.00 % 100.00 % = TOTAL OXIDE


Crystallography: Isometric – Hexoctahedral
Crystal Habit: As well formed octahedrons to about 15 mm.
Twinning: None known


Cleavage: n/a
Fracture: n/a
Tenacity: Brittle
Moh’s Hardness: n/a
Density: n/a
Luminescence: Not Fluorescent
Radioactivity: Not Radioactive


Color: Yellowish-Orange to Orangish Yellow, Emerald Green to deep Green
Transparency: Transparent to Translucent
Luster: Adamantine
Refractive Index: 2.030  Isotropic
Birefringence: 0.00 (Isotropic)
Dispersion: n/a
Pleochroism: n/a