Editorial Feature

Carlfriesite - Occurrence, Properties, and Distribution

May 28 2014

Carlfriesite was first discovered in 1975 from the Oriental (Bambollita) mine, north-east of the Moctezuma (Bambolla) mine, 12km south of Moctezuma, Sonora, Mexico.

It was named after Carl Fries, Jr. (1910-1965), U.S. Geological Survey and the Geological Institute of the National University, Mexico City, Mexico.

Properties of Carlfriesite

The following are the key properties of Carlfriesite:

Cell Data
- Space Group: C2/c
- a = 12.576(2)
- b = 5.662(3)
- c = 9.994(2)
- β = 115.56(3)°
- Z = 4

Crystal Data
- Monoclinic
- Point Group: 2/m
- As euhedral prismatic crystals, to 5mm, with an “axe head” appearance due to {010} and other forms being curved, in radial sprays;typically in botryoidal crusts
- X-ray Powder Pattern: 3.167 (10), 3.082 (9b), 5.063 (6), 2.832 (6), 3.369 (4), 4.825 (3), 2.698 (3)

Chemical Composition

Elements	Content 1	Content 2	Content 3
TeO₂	87	89.5	57.94
CaO	10.2	10.5	10.18
H₂O	6.5	-	-
TeO₃	-	-	31.88
Total	103.7	100	100

Optical Properties
- Optical Class: Biaxial (–)
- Pleochroism: Weak; in yellow
- Orientation: Y = b; X ^ c = 28°.
- Absorption: X = Y < Z
- α = 1.982
- β = 2.095
- γ = 2.19
- 2V(meas.) = 80°
- 2V(calc.) = 79°

Estimated Properties

Electron density	Bulk density (electron density) = 4.97 g/cm³ note: Specific gravity of Carlfriesite = 5.7 g/cm³
Photoelectric	PE_Carlfriesite = 245.73 barns/electron U= PE_Carlfriesite x ρ Electron density = 1220.46 barns/cm³
Fermion index	Fermion index = 0.05 Boson index = 0.95
Radioactivity	Carlfriesite is not radioactive

How to Identify Carlfriesite

Carlfriesite is a yellow mineral with distinct cleavage and yellow streak.

The density of the mineral is 6.3 g/cm³, and its hardness is 3.5.

Global Distribution

Carlfriesite is widely distributed in the Oriental (Bambollita) mine, north-east of the Moctezuma (Bambolla) mine, 12km south of Moctezuma, Sonora in Mexico.