Diopside Value, Price, and Jewelry Information


DIOPSIDE: New York (2.15), Kenya (0.75, chrome diopside), USSR (3.5, chrome diopside). Photo © Joel E. Arem, PhD, FGA. Used with permission.

Diopside Value

Highest values go to clarity, color, cutting.

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Diopside Value via Gem Price Guide
Chrome Diopside 1 to 2 carats 2 carats plus
Faceted to /ct to /ct
Black Star All sizes
to /ct

See the entire Gem Price Guide.

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Diopside Information

DataValue
NameDiopside
VarietiesChrome-Diopside, Lavrovite, Violane
Crystallography Monoclinic. Crystals often well formed, prismatic, stubby, also massive.
Colors Colorless, white, gray, pale green, dark green, blackish green, brown, yellowish to reddish brown, bright green (Cr variety); rarely blue. Schefferite is light to dark brown. Hedenbergite always dark green, brownish green, or black.
Luster Vitreous.
Polish Luster Vitreous to resinous
Fracture Luster Vitreous to resinous
Fracture Conchoidal to uneven; brittle.
Hardness 5.5-6.5
Toughness Poor
Specific Gravity Usually 3.29; range 3.22-3.38 for diopsde, higher if more Fe present.
Cleavage Perfect 1 direction.
Stone SizesNew York material provides cutting rough of fine quality and large size. The Italian, Swiss, and Austrian diopsides are usually smaller but of fine color. Diopside from Madagascar is very dark green and less attractive, up to about 20 carats. Chrome diopsides are known up to about 10-15 carats. Most diopside localities provide material that cuts 2-10 carat gems. American Museum of Natural History (New York): 38.0 (green, New York). Smithsonian Institution (Washington, D.C): 133.0 (black, star, India); 24.1 (black, catseye, India); 19.2 (green, Madagascar); 6.8 (yellow, Italy); 4.6 (yellow, Burma).
Heat SensitivityNo
Luminescence Blue or cream white in SW, also orange yellow; sometimes mauve in LW. May phosphoresce a peach color.
Spectral Chrome diopside has lines at 5080, 5050, 4900, plus fuzzy bands at 6350, 6550, 6700 and a doublet at 6900. Pale green diopside gives lines at 5050, 4930, and 4460.
Enhancements None known
Transparency Transparent to Opaque
UV LongGreen, mauve
UV ShortInert, blue/white, slightly yellowish/white, orange/yellow. May phosphoresce peach.
Absorption Spectrum Lines at 446, 493 and 505 nm. Chrome diopside, sharp lines at 490, 505, 508 nm, indistinct lines at 635, 655, 670 and double line at 690 nm.
Phenomena Asterism, (usually 4 ray, occasionally 6) Chatoyancy
Identifying Characteristics Star stones usually 4 rayed
FormulaCaMgSi2O6. Complete series to CaMgSi2O6 = Hedenbergite Intermediate members = Salite, Ferrosalite Ferrosalite rich in Mn and Zn = Jeffersonite Diopside rich in Mn = Schefferite Diopside rich in Mn and Zn = Zinc Schefferite (variety) Diopside rich in Cr = Chrome Diopside (variety) Diopside color varieties include baikalite. alalite and malacolite (Pale green) and violane (purple).
Pleochroism 
  • Diopside, none, yellow/green
  • Jeffersonite, dark brown/light brown
  • Schefferite, dark brown/light brown
  • Hedenbergite, pale green/green brown

Intermediate compositions have intermediate properties in the diopside-hedenbergite series; increasing iron content results in higher properties. The pleochroism of salite is: pale green/blue-green/yellow-green.

Diopside

Hendenbergite

Jeffersonite

Schefferite

Chrome Diopside

Optics
a

1.664- 1.695

1.716 -1.726

1.713

1.676

1.668-1.674

β

1.672 – 1.701

1.723 – 1.730

1.722

1.683

1.680

γ

1.695 – 1.721

1.741 -1.751

1.745

1.705

1.698-1.702

2V

50-60°

52-62°

74°

60°

55°

Density

3.22-3.38

3.50 -3.56

3.55

3.39

3.17-3.32

Birefringence

0.024-0.031

0.025-0.029

0.032

0.031

0.028

Pleochroism

none

pale green / green-brown

dark/light brown

dark/light brown

yellow/green

Occurrence: in Ca-rich metamorphic rocks; in kimberlite (Cr-diopside).

Burma: yellow faceted gems; also catseyes and pale green faceting material.

Madagascar: very dark green cutting material. Sri Lanka: cuttable pebbles.

Ontario, Canada: green faceting material.

Quebec, Canada: red-brown material that cuts gems to 2 carats.

Ala, Piedmont, Italy: fine green diopside (alalite is local name).

St. Marcel, Piedmont, Italy: violet variety of diopside (violane).

Zillerthal. Austria: fine green crystals, some transparent.

Georgetown, California: green diopside. Crestmore, California: large crystals (non-gem).

DeKalb, New York: fine transparent green crystals up to several inches in length.

Slyudyanka, USSR: green crystals (baikalite or malacolite); and chrome diopside.

Outokumpu, Finland: fine deep green Cr-diopside.

Nammakal, India: star stones and catseyes, also dark green facetable material.

Franklin, New Jersey: jeffersonite, schefferite, and Zn-schefterite

Långban, Sweden: jeffersonite, schefferite, and Zn-schefferite.

Kenya: chrome diopside.

Comments: Violane has been used for beads and inlay—transparent material is always very tiny. The color of this material is deep violet or blue and is very rare. Catseye material cuts extremely sharp eyes, the best being from Burma. Faceted diopside is not extremely rare, but large (over 15 carats) clean stones are. Colors are usually dark, so a bright and attractive gem is most desirable. Hedenbergite and the intermediate varieties tend always to be opaque except in very thin splinters. Chrome diopside, quite rare in sizes over 3-4 carats, has become available in commercial quantities from the USSR. The color is excellent, with Cr content about 0.5% by weight.

Name: Greek words meaning appearing double.

 

Variety Names:

Diopside, (CaMgSi2O6) runs in a solid-state series to hedenbergite, (CaFeSi2O6)

Salite, Ferrosalite, intermediates between diopside and hedenbergite.

Jeffersonite is ferrosalite plus Mn and Zn

Schefferite is diopside plus Mn

Zinc Schefferite is diopside plus Mn and Zn

Also:

Alalite, colorless to light green

Cat’s Eye diopside

Chrome diopside, deep green coloring from chromium, usually transparent

Malacolite, light colored, translucent stones.

Star diopside

Violane, massive, translucent to opaque, blue/violet. Rare.

Trade Names:

Tashmarine, green diopside