faceted diopside gemsfaceted diopside gems

Diopside Value, Price, and Jewelry Information


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.

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

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Diopside Value

Highest values go to clarity, color, cutting.

Identifying Characteristics

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

 


Joel E. Arem, Ph.D., FGA

Dr. Joel E. Arem has more than 60 years of experience in the world of gems and minerals. After obtaining his Ph.D. in Mineralogy from Harvard University, he has published numerous books that are still among the most widely used references and guidebooks on crystals, gems and minerals in the world.

Co-founder and President of numerous organizations, Dr. Arem has enjoyed a lifelong career in mineralogy and gemology. He has been a Smithsonian scientist and Curator, a consultant to many well-known companies and institutions, and a prolific author and speaker. Although his main activities have been as a gem cutter and dealer, his focus has always been education. joelarem.com

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