Diopside is a mineral with a hardness of 6 out of 10 on the Mohs scale of mineral hardness [?]. These Monoclinicly structured gems are made of calcium magnesium silicate, their full chemical compound being CaMg(SiO3)2.

Diopside is a type of Clinopyroxene, which are abundant, rock-forming minerals. These are embedded and surface-growing crystals, short columnar, and tabular, almost square or octagonal in cross section. It is the magnesium-bearing end member in the isomorphous, monoclinic diopside-hedenbergite series, a complete solid solution series in which two intermediate members, salite and ferrosalite, have been identified.

It is a silicate of calcium and magnesium.

It is bronzy, metallic-looking, with perfect cleavage. It appears more often in granular, rodlike or fibrous, radiating aggregates, in pale-green, blue, white, yellow, or brown. It is transparent to translucent with vitreous luster. Its color ranges from bottle green to blackish green, but also bright green or dull yellowish green. In some cases it is semiopaque, with internal fibrosity.

It fuses with difficulty to a green glass and is insoluble in acids.

Along with hedenbergite, it occurs in igneous and metamorphic rocks, diopside particularly in metamorphosed impure limestone, and in dolomitic marbles associated with other calcium silicates. It also appears in metasomized seams or lenses in serpentinized rocks (rodingites). Chromium-bearing diopside is typical of kimberlites. Salite is typical of some hypabyssal rocks derived from alkaline basalt magmas, and comes from Sala (Sweden), and other places in Finland, Scotland, Greenland, and New Zealand. Ferrosalite has been discovered in gneiss and metasomized contact rocks (skarns) in Fabian Mine (Sweden) and in St. Lawrence County, New York (USA).

Magnificent, clear, often complex crystals are found in Italy - in Val di Fassa (Trento), in calcareous blocks ejected by Vesuvius, as Monte Cervandone (Val d'Ossola), alalite from Pian della Mussa in Val d'Ala (Turin), in the Binnental (Switzerland), and at DeKalb and Gouverneur, New York (USA). Deposits are also found in Erzebirge (Germany), the Zillertal (Austria), baikalite, a dark green variety from the Urals and Lake Baikal (Soviet republics), Nordmarken (Sweden), cat's-eye chrome diopside from Myanmar (Burma).

Its bright, emerald-green variety is called "chrome diopside" and is a gemstone. Its dark-green form contains vanadium and is called "lavrovite," or "chrome enstatite." These come from kimberlites in South Africa and Siberia.

The purple manganese-bearing variety is known as "violane." This is typical of St. Marcel (Val d'Aosta, Italy).

Diopside displaying asterism when the stone is cut en cabochon is called "star diopside," and is seen quite often on the market for minor gemstones. Star stones with four notably sharp rays come from Myanmar, and four-rayed star diopside has been reported from southern India. It has only binary symmetry, and the star has four rays, two of which are straight, while the other two, not at right angles to the first pair, look slightly wavy. Sometimes, oriented needlelike surface crystalline inclusions are clearly visible, especially from below. It is sometimes passed off as "star sapphire," although the resemblance is highly superficial.

The variety of various colored granular diopside is called "coccolite."

Other names for diopside include "alacolite," "chromdiopside,"

Misleading terms include "chloromelanite jade" for gem quality green diopside resembling jade.

"Diopside jadeite" or "Diopside jade" is a pyroxene intermediate between jadeite and diopside from Tuxtla, Mexico.

The specific gravity [?] for Diopside is 3.29, it's refractive index [?] is 1.66-1.72, and it's double refraction [?] is 0.029.

History

Diopside derives its name from the Greek "dis" and "opsis" meaning "double vision," because it is clearly birefringent. Some of the magnesium may be replaced by iron.

Industrial Usages

Some transparent varieties are faceted into gems. the semiopaque specimens exhibit chatoyancy or asterism if appropriately cut. It is not a very well-known gem, outside the areas where it is mined and cut. The brilliant green chrome diopside varieties are of low value. The dark or light green varieties are worth still less. It is neither imitated nor produced synthetically. But the mineral is of interest to collectors and petrologists.

You May Also Like...

Hessonite

Hessonite: Hessonite is the brown-orange variety of Grossular, a nesosilicate in the Garnet group, with an isometric crystal system. It appears with dodecahedral or trapezohedral crystals, cinnamon-brown to orange because of its iron content. Its color matches that of the oil of cinnamon. It also appears as golden-yellow, yellow-brown, or reddish-brown. It is very hard, heavy, fragile, has no cleavage. It (read full)

Vesuvianite

Vesuvianite: Vesuvianite is a hydrous calcium magnesium aluminum silicate with a tetragonal crystal system. It is the preferred name used by mineralogists for all transparent varieties of Idocrase, the name used by gemmologists. It is a gem mineral that appears in diverse colors, and thus is prized by collectors. A compact green variety of vesuvianite that looks like jade is known as californite. A greenish-b (read full)

Epidote

Epidote: Epidote is widespread, forms a continuous series of minerals, ending with clinozoisite, which contains no iron. It occurs as crystals elongated and often striated parallel to length, and also as massive, fibrous, or granular habits. Epidote has a yellow-green color, ranges from yellowish-greenish to greenish-black. It has vitreous luster, and is transparent to nearly opaque. It has one perfe (read full)

Lapis Lazuli

Lapis Lazuli: Lapis lazuli is composed of several minerals in small quantities - augite, calcite, diopside, mica, hauynite, hornblende, pyrite. Because of this some experts consider it a rock, more than a mineral. The main ingredient of Lapis lazuli is Lazurite. It has a uniform, massive, or sometimes granular appearance, with fairly distinct crystals. It is semi-opaque to opaque, with a surface that can take (read full)

Enstatite

Enstatite: Enstatite is the most common silicate under the Orthopyroxene group in the larger classification of Pyroxene minerals (which are rock-forming silicates). Orthopyroxenes form a chemical series composed of the magnesium-rich enstatite, and the iron-containing bronzite and hypersthene. It has an orthorhombic crystal system and appears rarely as stubby, prismatic crystals, but more commonly in fibr (read full)

Tags

Terms

Double Refraction or dr is the ability of a mineral to separate a refracted ray of light into 2 rays. If held over an image or text it will display the object 2x its original size.

Mohs Scale of Mineral Hardness is the standard used to categorize a mineral's ability to resist scratching. It gets its name from Friedrich Mohs, the German geologist who first created the scale.

RI or Refractive Index defines light's ability to move through the mineral or in a general sense, any material.

SG or Specific Gravity is the ratio of the weight of any substance to that of pure water at temperature of 3.98°C(39.2°F) and standard atmospheric pressure. This is important to note when actively seeking these minerals in the wild. Minerals with a higher SG will settle below material with a lower sg over time.