Diopside
Current inventory:  0 gems
 

  
Diopside is named from the Greek words dis meaning double and opsis meaning appearance; apparently for the two possible orientations of the prism zone.

Discovered in 1800; IMA status: Valid (pre-IMA; Grandfathered)

Chemistry

Chemical Formula:

CaMgSi₂O₆ 

Calcium Magnesium Silicate

Molecular Weight:

216.55 gm

Composition:

Calcium

18.51 %

Ca

25.90 %

CaO

Magnesium

11.22 %

Mg

18.61 %

MgO

Silicon

25.94 %

Si

55.49 %

SiO₂

Oxygen

44.33 %

O

100.00 %

100.00 %

= TOTAL OXIDE

Classification

Mineral Classification:

Silicates (Germanates)

Strunz 8th Ed. ID:

8/F.01-50

Nickel-Strunz 10th Ed. ID:

9.DA.15

9 : SILICATES (Germanates)
D : Inosilicates
A : Inosilicates with 2-periodic single chains, Si₂O₆; pyroxene family

Related to:

Pyroxene Group. Clinopyroxene Subgroup. Diopside - Hedenbergite Series. Diopside - Johannsenite Series. Dimorph of Boehmite.

Members of Group:

Pyroxene Group: Canaanite, Clinopyroxene Subgroup, Orthopyroxene Subgroup

Members of Subgroup:

Clinopyroxene Subgroup: Aegirine, Augite, Clinoenstatite, Clinoferrosilite, Diopside, Essenite, Grossmanite, Hedenbergite, Jadeite, Jervisite, Johannsenite, Kanoite, Kosmochlor, Kushiroite, Namansilite, Natalyite, Petedunnite, Pigeonite, Spodumene

Varieties:

Baikalite, Blue Diopside, Canaanite, Chromian Diopside, Fedorovite, Lavrovite, Schefferite, Traversellite, Violane, Zinc-Schefferite

Synonyms:

Acantoide, Acimite-diopside, Alalite, Bistagite, Chrome-Augite, Coccolite, Dekalbite, Kokkolith, Leucaugite, Malacolite, Malakolith, Mussite (of Bonvoisin), Protheite, Sahlite, Salite, Tashmarine

Crystal Data

Crystallography:

Monoclinic - Prismatic

Crystal Habit:

As prismatic crystals with nearly square cross sections, to 50 cm; granular, columnar, lamellar massive.

Twinning:

Simple or multiple twins on {100} or {010} common.

Physical Properties

Cleavage:

Distinct/Good on {110}; partings on {100} and probably {010}

Fracture:

Irregular/Uneven to Conchoidal

Tenacity:

Brittle

Moh's Hardness:

5.5 - 6.5

Density:

3.22 - 3.38 (g/cm³)

Luminescence:

None

Radioactivity:

Not Radioactive

Optical Properties

Color:

Colorless, white, yellow, pale to dark green, black; colorless in thin section.

Transparency:

Transparent to Opaque

Luster:

Vitreous, Dull

Refractive Index:

1.664 - 1.695  Biaxial ( + )

Birefringence:

0.024 - 0.031

Dispersion:

Weak to Moderate; r > v

Pleochroism:

None

Occurances

Geological Setting:

Typical of metamorphosed siliceous Ca, Mg-rich rocks of the pyroxene-hornfels or epidote-amphibolite facies; common in skarns, Ca, Mg-rich gneisses and schists, and some kimberlites and peridotites. Less common in alkalic olivine basalts and andesites.

Common Associations:

Calcite, Chondrodite, Clinohumite, Forsterite, Grossular, Monticellite, Quartz, Scapolite, Tremolite, Vesuvianite, Wollastonite

Common Impurities:

Fe, V, Cr, Mn, Zn, Al, Ti, Na, K

Type Locality:

Wide spread occurance.

Year Discovered:

1800

View mineral photos:

Diopside Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Diopside is a member of the Clinopyroxene Subgroup of minerals that includes Aegirine, Diopside, Hedenbergite, Hypersthene, Jadeite, Petedunnite and Spodumene. It is an important rock forming mineral in some metamorphic and igneous rocks and is also found in meteorites.

Diopside is available in several varieties and colors from many locations, but the deep green, chromium-rich, Chrome Diopside is the most popular and most well known. Chrome Diopside is somewhat rare and is mostly available from the Ural Mountains in Russia. Another variety of Diopside is called Violane and is blue, violet or purple and found in Italy. Tashmarine is a variety of Diopside that is a trade name for yellowish green material originally found in China. There is also a green "cat's eye" variety and a very dark "Star Diopside" with an often very distinct 4-rayed star. Ordinary Diopside is usually white or pale green.

Distribution: Selected localities for fine crystals follow: at Schwarzenstein, Zillertal, and near Prägraten, Tirol, Austria. From Ala, Piedmont, and St. Marcel, Val d'Aosta, Italy. At Otokumpu, Finland. In Russia, at the Akhmatovsk deposit, near Zlatoust, Ural Mountains; large crystals in the Inagli massif, 30 km west of Aldan, Yakutia; and along the Slyudyanka River, near Lake Baikal, Siberia. In Canada, many localities; in Ontario, at Bird's Creek, Eganville, Dog's Lake, Littlefield, and Burgess; in Quebec, at Wakefield, Brompton Lake, near Magog, and in the Jeffrey mine, Asbestos. In the USA, at DeKalb, St. Lawrence County, Natural Bridge, Jefferson County, Sing Sing, near Ossining, Westchester County, New York; and at Ducktown, Polk County, Tennessee. At Ampandrandava and Andranodambo, Taolanaro (Fort Dauphin), Madagascar. Large gemmy crystals from the Kunlun Mountains, Sinkiang Uighur Autonomous Region, China. From Tange-Achin, Kandahar Province, Afghanistan. Found near Jaipur, Rajasthan, India. At Khapalu and Chamachu, Pakistan.
 

  
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