|
Click on a
letter above to view the list of gems. |
|
|
|
| Axinite-(Fe) is named
from the Greek
word acine meaning ax in allusion to the acute shape of typical crystals.
The modifier Ferro is from the Latin word ferrum meaning "iron" in reference to the Fe in the chemical formula.
| Discovered
in 1909;
IMA
status: Valid (pre-IMA; Grandfathered) |
|
Chemistry
|
|
|
Chemical
Formula: |
Ca2Fe2+Al2(BO3)Si4O12(OH)
|
|
Calcium
Iron Aluminum Boron Sorosilicate Hydroxide |
Molecular
Weight: |
570.12 gm
|
Composition: |
Calcium |
14.06 % |
Ca |
19.67 % |
CaO |
|
Aluminum |
9.47 % |
Al |
17.88 % |
Al2O3 |
|
Iron |
9.80 % |
Fe |
12.60 % |
FeO |
|
Silicon |
19.71 % |
Si |
42.16 % |
SiO2 |
|
Boron |
1.90 % |
B |
6.11 % |
B2O3 |
|
Hydrogen |
0.18 % |
H |
1.58 % |
H2O |
|
Oxygen |
44.90 % |
O |
|
|
|
|
100.00 % |
|
100.00 % |
= TOTAL OXIDE |
|
|
Classification
|
|
|
Mineral
Classification: |
Silicates
(Germanates)
|
Strunz 8th
Ed. ID:
|
8/E.06-10
|
Nickel-Strunz 10th
Ed. ID:
|
9.BD.20
|
|
9 : SILICATES (Germanates)
B : Sorosilicates D : Si2O7
groups, with additional anions; cations in tetrahedral [4] and greater
coordination
|
Related
to: |
Axinite
Group. Axinite-(Fe)-Axinite-(Mg) Series. Iron analog of Axinite-(Mg) and Axinite-(Mn)
|
Members
of Group: |
Axinite
Group: Axinite-(Fe), Axinite-(Mg), Axinite-(Mn), Tinzenite
|
Varieties: |
Feraxinite,
Ferro-Axinite
|
Synonyms: |
None
|
|
|
Crystal
Data
|
|
|
Crystallography:
|
Triclinic - Pinacoidal
|
Crystal
Habit:
|
Crystals
typically flattened, axe-head-shaped, to 20 cm; granular,
massive.
|
Twinning:
|
None
|
|
|
Physical
Properties
|
|
|
Cleavage: |
Distinct
on {100}, Poor on {001} and {110}
|
Fracture: |
Irregular/Uneven
to Conchoidal
|
Tenacity:
|
Brittle
|
Moh's
Hardness: |
6.5
- 7.0
|
Density:
|
3.25
- 3.28 (g/cm3)
|
Luminescence:
|
None
|
Radioactivity:
|
Not
Radioactive
|
|
|
Optical
Properties
|
|
|
Color: |
Brown, Purplish blue, Gray, Greenish yellow
|
Transparency: |
Transparent to Subtransparent
|
Luster: |
Vitreous
(Glassy) |
Refractive
Index: |
1.672 - 1.701 Biaxial
( - ) |
Birefringence: |
0.0090
- 0.0110 |
Dispersion: |
Strong, r < v
|
Pleochroism: |
X
= colorless, yellow, light brown, yellow brown, or pale green;
Y
= colorless, deep yellow, deep blue, pale violet, or violet;
Z
= colorless, pale green, olive yellow, brown, or dark violet
|
|
|
Occurances
|
|
|
Geological
Setting: |
In
low- to high-grade regionally metamorphosed rocks, in
contact metamorphosed rocks, and in pegmatites. |
Common
Associations: |
Epidote,
Tremolite, Calcite (London Bridge, Australia); Prehnite,
Epidote, Actinolite, Vesuvianite (Luning, Nevada, USA)
|
Common
Impurities: |
n/a
|
Type
Locality: |
St. Christophe-en-Oisans, Bourg d'Oisans, Isère,
Rhône-Alpes, France |
Year
Discovered: |
1909
|
View
mineral photos: |
Axinite-(Fe)
Mineral Photos and Locations |
|
|
More
Information
|
|
|
|
Mindat.org
Webmineral.com
|
|
|
Axinite-(Fe)
is a somewhat rare gem and is usually intensely
trichroic with brown and purple colors being dominant. Axinite-(Fe)
is the iron analog of Axinite-(Mg)
which is the Magnesium analog.
It is difficult to find material without internal flaws
and feathers. Despite the inclusions, Axinite is a magnificent
gem because of its rich colors and brilliance.
There
are many localities for Axinite-(Fe), even for fine
crystals. On Roscommon Cliff and in the Botallack mine,
St. Just, Cornwall, England. From Bourg d'Oisans, Isère,
France. In the Maderantal, Uri, Switzerland. Extraordinary
crystals from the Puiva deposit, about 100 km west-northwest
of Saranpaul, Subpolar Ural Mountains; at Zlatoust,
Ural Mountains; and elsewhere in Russia. At Skardu,
Pakistan. In the Obira mine, Bungo, Oita Prefecture;
the Toroku mine, Miyazaki Prefecture; and elsewhere
in Japan. In the USA, from Coarse Gold, Madera County,
near Yreka, Siskiyou County, and New Melones Lake, Calaveras
County, California; and from Elkhorn, Jefferson County,
Montana. In Canada, found near Hope, British Columbia,
and in the Moneta mine, Timmins, Ontario. From Trinidad,
Baja California, Mexico. At Vitoria da Conquista, Bahia,
Brazil.
|
Axinite-(Fe)
gems for sale:
We
have not photographed the Axinite-(Fe) gems yet. Please
check back soon.
|
|