|
| Chondrodite
|
|
Discovered
in 1817; IMA
status:
Valid (pre-IMA; Grandfathered)
|
Chemistry
|
|
|
Chemical
Formula: |
(Mg,Fe2+)5(SiO4)2(F,OH)2
|
|
Magnesium
Iron Silicate Fluoride Hydroxide |
Molecular
Weight: |
382.12 gm
|
Composition: |
Magnesium |
23.85 % |
Mg |
39.55 % |
MgO |
|
Iron |
18.27 % |
Fe |
23.50 % |
FeO |
|
Silicon |
14.70 % |
Si |
31.45 % |
SiO2 |
|
Hydrogen |
0.13 % |
H |
1.18 % |
H2O |
|
Oxygen |
35.59 % |
O |
|
|
|
Fluorine |
7.46 % |
F |
7.46 % |
F |
|
|
-
% |
F |
-3.14 % |
-O=F2 |
|
|
100.00 % |
|
100.00 % |
= TOTAL OXIDE |
|
|
Classification
|
|
|
Mineral
Classification: |
Silicates
(Germanates)
|
Strunz 8th
Ed. ID:
|
8/B.04-20
|
Nickel-Strunz 10th
Ed. ID:
|
9.AF.45
|
|
9 : SILICATES (Germanates)
A : Nesosilicates F : Nesosilicates with additional anions; cations in [4], [5] and/or only [6] coordination
|
Related
to: |
Humite
Group. Dimorph of
Ribbeite. Isostructural with Alleghanyite, Chegemite, Edgrewite, Hydroxylchondrodite, Hydroxylclinohumite, Kumtyubeite, Manganhumite, Norbergite, Reinhardbraunsite, Sonolite.
|
Members
of Group: |
Humite
Group: Alleghanyite,
Chegemite, Chondrodite, Clinohumite, Edgrewite, Humite, Hydroxylchondrodite,
Hydroxylclinohumite, Jerrygibbsite, Kumtyubeite, Leucophoenicite,
Manganhumite, Norbergite, Reinhardbraunsite, Ribbeite,
Sonolite
|
Varieties: |
None
|
Synonyms: |
Brocchite,
Brucite (of Gibbs), Condrodite, Fluosiderite (F-rich Chondrodite),
ICSD 15180, Maclureite (of Nuttall),
PDF 12-52, Prolectite
|
|
|
Crystal
Data
|
|
|
Crystallography:
|
Monoclinic
- Prismatic
|
Crystal
Habit:
|
Crystals
rare, varied in habit, typically flattened || [010],
to 10 cm. Commonly as rounded grains, massive.
|
Twinning:
|
On
{001}, common, simple and lamellar; possibly || {015}
and {305}.
|
|
|
Physical
Properties
|
|
|
Cleavage: |
Indistinct
on {100};
parting on {001}
|
Fracture: |
Conchoidal
|
Tenacity:
|
Brittle
|
Moh's
Hardness: |
6.0 - 6.5
|
Density:
|
3.1 - 3.2 (g/cm3)
|
Luminescence:
|
Not
all specimens exhibit fluorescence. Fluorescent specimens
show
orange yellow under SW UV, orange under LW UV. |
Radioactivity:
|
Not
Radioactive
|
|
|
Optical
Properties
|
|
|
Color: |
Light
yellow, yellow, brown, red; in thin section, pale yellow
or brown to colorless
|
Transparency: |
Transparent
to translucent |
Luster: |
Vitreous
to resinous |
Refractive
Index: |
1.592 - 1.675 Biaxial
( + )
|
Birefringence: |
0.027 - 0.032
|
Dispersion: |
Weak
to strong; r > v
|
Pleochroism: |
X
= colorless, very pale yellow, brownish yellow; Y
= colorless, yellow-green; Z = colorless, pale
green
|
Anisotropism: |
Fairly
strong; color in reflected light: white
|
|
|
Occurances
|
|
|
Geological
Setting: |
In
contact metamorphic zones, in limestones and dolostones,
associated with felsic to alkalic plutonic rocks, especially
with Fe-B-F metasomatism; in a carbonatite. |
Common
Associations: |
Phlogopite,
Spinel, Magnetite, Grossular, Wollastonite, Forsterite,
Monticellite, Cuspidine, Diopside, Calcite
|
Common
Impurities: |
Ti,
Al, Mn |
Type
Locality: |
Skräbböle quarry, Pargas (Parainen), Southwestern Finland Region, Finland
|
Year
Discovered: |
1817
|
View
mineral photos: |
Chondrodite
Mineral Photos and Locations |
|
|
Unusual
Gem Categories
|
|
|
|
Fluorescent
Gems |
|
|
More
Information
|
|
|
|
Mindat.org
Webmineral.com
|
|
|
Chondrodite is
a member of the Humite Group of minerals that includes
Chondrodite,
Clinohumite, Humite and Norbergite. Faceted Chondrodite
is fairly rare. Faceted
gems can be beautiful in colors of light yellow, yellow,
brown and deep red to deep orangish red.
Some Chondrodite gems may exhibit fluorescence of orangish-yellow under shortwave
(SW) UV light and orange under longwave (LW) UV light.
If you hover your cursor over the picture above, you
will see the Chondrodite gem exhibiting fluorescence
under UV light.
Chondrodite
was named in 1817 by Swedish historian Baron Abraham Constantin Mouradgea d'Ohsson
(1779-1851) from the
Greek word Χόνδρος (chondros) meaning
grain in allusion to its habit of occurring in isolated
grains. d'Ohsson called Chondrodite "a yellow stone from Pargas".
There are several sources of Chondrodite around the
world, but only a few produce facetable crystals. One source of small gemmy crystals
is the Tilly Foster Mine in Brewster, New York. Other
sources are Badakhshan (Badakshan; Badahsan) Province,
Afghanistan; Palabora mine, Loolekop, Phalaborwa, Limpopo Province,
South Africa; and Mogok, Sagaing District, Mandalay Division, Myanmar
(Burma).
Distribution:
from Pargas, Hangelby, and Sibbo, Finland. At Kafveltorp,
near Kopparberg, Sweden. From Monte Somma and Vesuvius,
Campania, Italy. At Le Chipal, Vosges, France. From
Bhandara, Maharashtra, India. In the USA, fine crystals
from the Tilly Foster mine, Brewster, Putnam County,
and Amity, Orange County, New York; at Franklin and
Sparta, Sussex County, New Jersey; Johnson Camp, Cochise
County, and the Lakeshore mine, Pinal County, Arizona;
and Crestmore, Riverside County, California. From Bancroft,
Ontario, Canada. In the Loolekop carbonatite, Transvaal,
South Africa. A few other localities are known.
|
Chondrodite
gems for sale:
We
have not photographed our Chondrodite
gems yet. Please
check back soon.
|
|