Cacoxenite (inclusions in Quartz and Amethyst)
Current inventory:  0 gems
 

  
Cacoxenite is named from the Greek words for bad guest due to the fact that its phosphorous content lessens the quality of iron smelted from ore containing it.

Discovered in 1825;   IMA status:  Valid (pre-IMA; Grandfathered)

Chemistry

Chemical Formula:

Fe²⁺₂₄Al(PO₄)₁₇O₆(OH)₁₂ · ~75(H₂O)

Hydrated Iron Aluminum Phosphate Oxide Hydroxide

Molecular Weight:

4,481.51 gm

Composition:

Aluminum

3.76 %

Al

7.11 %

Al₂O₃

Iron

23.37 %

Fe

30.06 %

FeO

Phosphorus

11.75 %

P

26.92 %

P₂O₅

Hydrogen

3.64 %

H

32.56 %

H₂O

Oxygen

57.48 %

O

100.00 %

100.00 %

= TOTAL OXIDE

Classification

Mineral Classification:

Phosphates

Strunz 8th Ed. ID:

7/D.11-50

Nickel-Strunz 10th Ed. ID:

8.DC.40

8 : PHOSPHATES, ARSENATES, VANADATES
D : Phosphates, etc. with additional anions, with H₂O
C : With only medium-sized cations, (OH, etc.):RO₄ = 1:1 and < 2:1

Related to:

None

Varieties:

None

Synonyms:

Cacoxene

Crystal Data

Crystallography:

Hexagonal - Dihexagonal Dipyramidal

Crystal Habit:

Crystals, may be crudely hexagonal, acicular along [0001], typically in compact concentric spherical to radial aggregates, to 8 mm; in bundles, randomly fibrous; as coatings or an intergranular cement.

Twinning:

None

Physical Properties

Cleavage:

None

Fracture:

Irregular/Uneven

Tenacity:

Brittle

Moh's Hardness:

3.0 - 4.0

Density:

2.20 - 2.60 (g/cm³)

Luminescence:

None

Radioactivity:

Not Radioactive

Other:

Readily soluble in acids.

Optical Properties

Color:

Yellow to Brownish Yellow or Reddish Orange, Golden Yellow, deep Orange, rarely Greenish

Transparency:

Semi-Transparent to Translucent

Luster:

Silky

Refractive Index:

1.575 - 1.656  Uniaxial ( + )

Birefringence:

0.060

Dispersion:

None

Pleochroism:

Visible; 0 = pale yellow; E = canary-yellow to yellow-orange

Occurances

Geological Setting:

A common accessory mineral in oxidized magnetite and "limonite" iron ores; in Fe,Mn-bearing novaculites; a rare constituent of iron-rich sediments and soils.

Common Associations:

Beraunite, Dufrenite, Rockbridgeite, Strengite, "Limonite", Magnetite, Wavellite.

Common Impurities:

Al

Type Locality:

Hrbek Mine, Svatá Dobrotivá (St Benigna), Beroun (Beraun), Central Bohemia Region, Bohemia (Böhmen; Boehmen), Czech Republic

Year Discovered:

1825

View mineral photos:

Cacoxenite Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Cacoxenite is a fairly common phosphate mineral that is usually found as minute, acicular, sperical radiating bundles or as golden to brownish yellow needle inclusions in Quartz and Amethyst. It is beautiful as bright golden yellow, chatoyant needle inclusions in Quartz cabochons. Cacoxenite is available as small mineral specimens but somewhat rare as a gemstone. The best material for Quartz/Cacoxenite cabochons is from Bahia and Minas Gerais, Brazil.

Cocoxenite is widespread in small amounts. In the Czech Republic, from the Hrbek mine, Svatá Dobrotivá (St. Benigna); at Trenice; from Zbirov; and at Cerhovice. In Germany, from the Eleonore and Rotläufchen mines, near Giessen, Hesse, and at Hiihnerkobel, near Zwiesel, Bavaria. In France, at Rochefort-en-Terre, Morbihan. From Shanagolden, County Limerick, Ireland. At Kiruna, Sweden. In the USA, from the Palermo #1 mine, near North Groton, Grafton County, New Hampshire; from Pennsylvania, at Hellertown, Northampton County, Moore's Mill, Cumberland County, and Noble's mine, Lancaster County On Indian Mountain, Cherokee County, Alabama, groups large for the species; in the Wilson Springs (Potash Sulphur Springs) mine, Garland County, from the Avant claim, about three km southwest of Shady, and at Three Oak Gap, Polk County, Arkansas; in the Vanleer mine, Iron City, Lawrence County, Tennessee; from the Palmetto mine, southwest of Bartow, Polk County, Florida.
 

  
Cacoxenite gems for sale:

We have not photographed our Cacoxenite gems yet. Please check back soon.