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The Minerals & Gemstones Azurite & Malachite


 

Azuritr & Malachite mineral specimen
PHYSICAL PROPERTIES:
AZURITE FORMULA: Cu3(CO3)2(OH)2
COMPOSITION: Basic copper carbonate
COLOR: Blue to very dark blue
STREAK: Light blue
HARDNESS: 3½ - 4
TRANSPARENCY: Opaque.
SPECIFIC GRAVITY: 3.7 - 3.9.
LUSTER: Submetallic, vitreous, or dull.
CLEAVAGE: 2,1 ; 3,2
FRACTURE: Conchoidal. Or Splintery.
GROUP: Carbonates.
TENACITY: Brittle.

MALACHITE FORMULA: Cu3CO3(OH)2
COMPOSITION: Basic copper carbonate
COLOR: Light to dark green, sometimes banded
STREAK: Light green
HARDNESS: 3½ - 4
TRANSPARENCY: Opaque.
SPECIFIC GRAVITY: 3.9 - 4.0.
LUSTER: Vitreous, silky or dull.
CLEAVAGE: 1,1 - basal.
FRACTURE: Not usually noticeable, Splintery
GROUP: Carbonates.
TENACITY: Brittle.

AZURITE CRYSTAL FORMS: and AGGREGATES:
(Monoclinic) Usually in small crystals, which are in prismatic, tabular, or equidimensional form. Crystals are frequently striated. Other forms are massive, crusty, radiating, fibrous, columnar, stalactitic, thin needles and in ball-like aggregates. Also occurs in dense groups of tabular or prismatic crystals.

MALACHITE CRYSTAL FORMS: and AGGREGATES:
(Monoclinic) Most common habit is as large crusts of microscopic crystals. Also occurs as bundles of thin long splinters. Large individual crystals are very rare and are usually pseudomorphs after Azurite. When they are not pseudomorphs of Azurite, they are prismatic, tabular, re-entrant twins, and (most commonly) thin splinters. Also occurs acicular, radiating, reniform, botryoidal, as banded masses, stalactitic, and as thin films coating other minerals.

PHYSICAL PROPERTIES:
Malachite and Azurite are both simple Copper carbonates. Azurite occurs as a secondary mineral in the oxidized zones of copper deposits. Where as Malachite occurs as an alteration product in the oxidized zones of copper deposits.

They are chemical twins. The only differences is that Azurite holds less water than Malachite. The green patina on weathered copper roofs is a form of Malachite. Both Malachite and Azurite are formed when carbon dioxide and water, weather copper ore or when copper ore weathers the mineral calcite. Azurite is found in shades of deep blue and is much more rare
then Malachite.

Azurite and Malachite are very often found together. Blue bladed azurite crystals blending with the rich green of malachite is a very pleasing mineral combination. A rarer Azurite mixture, known as "Bluebird", is Azurite mixed with dark red Cuprite

The massive, botryoidal, reniform, and stalactitic forms of Malachite have dense growths of tiny, fibrous needles and are almost always internally banded in different shades of green. These interesting bands and rich green colors, make Malachite a very apealing gemstone. Malachite also often forms as a mass with concentric bands of light and dark green. Specimens with concentric rings are highly prized.

Azurite commonly forms pseudomorphs over other minerals, retaining the original crystal shape of that mineral
. ( Pseudomorph: One mineral chemically replaces another mineral without changing the external form of the original mineral.) Pseudomorphs of Malachite after azurite are also common.

Sometimes Azurite undergoes a chemical change and loses some hydroxyl, altering the Azurite to Malachite, retaining the crystal shape of the original Azurite. Other times, only part of the Azurite is altered to Malachite, while the other part remains as Azurite. Such specimens are green on one end and blue on the other.

Linarite specimens are sometimes mistakenly sold as Azurite, since they both occur in the same locations and may strikingly resemble each other. However, simple tests on physical properties can accurately distinguish the two.

Although their massive forms are well known. Their crystalline forms are rare and only now becoming widely available to the average mineral collector. Many beautiful specimens of Azurite and Malachite containing wonderful combinations of other minerals,such as, Cuprite, Calcite, Chalcocite, Chalcopyrite, Chrysocolla, Copper and Limonite are now coming from
many old and new locations.


USES:
Malachite Is a fairly soft rock and is often used for small carvings. Be aware though, its dust is highly toxic! Malachite and Azurite are also very famous, popular semiprecious gemstones. Their many patterns and mixtures of dark blue and green, give cut gems and carvings a unique quality unlike that of any other stone. Malachite and Azurite are very popular among mineral collectors, They are also used as an ore of copper.

In anchent times Azurite and Malachite were crushed and used as pigments.


LOCALITIES:
Fine Azurite and Malachite specimens have been obtained from numerous places. In very early times an enormous deposit of Malachite with massive globular specimens was found in the Ural Mountains of Russia. More recently, large specimens, which may be the largest crystals found to date, are found in the Ongonja Mine Tsumeb, Namibia.

Malachite is most commonly found in the Democratic Republic of the Congo (formerly known as Zaire), as well as the Copper Queen Mine of Bisbee, Cochise Co., Arizona. In these mines, large Azurite crystals were found pseudomorphed by Malachite. Other Countries that produce large amounts of Malachite are Zambia, Namibia, Australia, Germany, Mexico, and the US

Good specimens have also come from Romania; Chile; Shaba; Chessy, France; Laurium, Greece; the Black Forest, Germany; Cornwall, England; Burra Burra, South Australia and Broken Hill, New South Wales, Australia. In Mexico it occurs in the San Carlos Mine in Mazapil, Zacatecas. In the US, most fine specimens are from numerous localities in Arizona, but the leading locality by quality and quantity is by far Bisbee, Cochise Co. Other localities in Arizona include Ajo and Tiger, Pinal Co.; and Clifton and Morenci, Greenlee Co. Azurite also occurs in the Rose Mine in Grant Co., New Mexico, Nevada Lode Mine, San Juan Co., Utah, the Tintic District, Juab Co., Utah; and elongated, tabular crystal clusters have come from La Salle Co., Utah. I did say numerous locations didn't I?


FACTS & HISTORY:
Azurite owes its name, to its azure-blue color and from the Persian word "lazhward", meaning "blue."Malachite gets it's name from the Greek, word "moloche", meaning "mallow," a reference to the mineral's leaf-green color.

Azurite and Malachite have been carved into ornaments and worn as jewelry for thousands
of years. In some ancient civilizations Malachite was thought to be a protection from evil if
worn as jewelry.

Malachite was a popular decorative stone in Czarist Russia, and was used to make the
columns of St. Isaac's Cathedral in Leningrad. Malachite also adorned many walls and
even whole rooms of other religious and public buildings.

The European name Chessylite is from a famous Azurite locality in Chessy, France.