Editorial Feature

Bartonite - Occurrence, Properties, and Distribution

May 12 2014

Bartonite was named after Paul Booth Barton Jr. who was born in 1930, an ore petrologist with the U.S. Geological Survey.

Properties of Bartonite

The following are the key properties of bartonite:

Cell Data
- Space group: I 4/mmm
- a = 10.424(1)
- c = 20.626(1)
- Z = 2

Crystal Data
- Tetragonal
- Point group: 4/m 2/m 2/m
- Anhedral masses, intergrown with pyrrhotite; rare elongated single crystals, to 50µm long
- X-ray powder pattern: 2.998 (100), 5.99 (77), 1.833 (40), 9.31 (27), 3.139 (27), 2.379 (25), 1.841 (25)

Chemical Composition

Elements	Content 1	Content 2
Fe	51.2	49.66
S	38.4	39.91
K	9.54	10.43
Cu	0.62	-
Ni	0.19	-
Co	0.11	-
Na	0.05	-
Cl	0.02	-
Total	100.13	100.00

Optical Properties
- R1–R2: (400) 21.7–18.3, (420) 16.7–14.4, (440) 17.7–17.2, (460) 18.4–18.6, (480) 19.4–19.5, (500) 19.7–20.6, (520) 20.3–21.4, (540) 20.9–21.8, (560) 21.9–22.7, (580) 22.7–23.2, (600) 23.4–23.7, (620) 23.9–24.3, (640) 24.7–25.1, (660) 25.0–25.5, (680) 25.2–26.1, (700) 26.4–26.5
- Pleochroism: Very weak

Estimated Properties

Electron density	Bulk density (electron density) = 3.20 g/cm³ note: Specific gravity of bartonite = 3.33 g/cm³
Photoelectric	PE_Bartonite = 18.21 barns/electron U=PE_Bartonite x ρ electron density= 58.34 barns/cm³
Fermion index	Fermion index = 0.01 Boson index = 0.99
Radioactivity	Bartonite is radioactive (barely detectable)

How to Identify Bartonite

Bartonite can be identified in the field by its black-brown color. Its opaque form has {112} distinct cleavage. This mineral has a metallic luster, with black streak. The fracture on this mineral is conchoidal. The density of bartonite is 3.305 g/cm³, with a hardness of 3.5 – approximate to a copper penny.

Global Distribution

Bartonite is distributed mainly in USA from Coyote Peak, near Orick, Humboldt Co. California.

Occurrence of Bartonite and Useful Mineral Association

Bartonite occurs in clots with other sulfides and silicates in an alkalic diatreme, which intruded Franciscan rocks.

It is often associated with minerals such rasvumite, nepheline, djerfisherite, erdite, pyrite, sphalerite, pyrrhotite, lollingite, magnetite, and phlogopite.