Name/Title
Azurite / MalachiteEntry/Object ID
2004.1.163Description
Chemical Composition: Cu3(CO3)2(OH)2
Crystal System: Orthorhombic System
Description: Common Name: Azurite / Malachite
Chemistry: Cu2(CO3)(OH)2, Copper Carbonate Hydroxide.
Group: Carbonates
Location: Arizona, U.S.A
Description: A deep blue azurite (blue copper carbonate) and green malachite (green basic copper carbonate) mixture, probably from Bisby, Arizona. Surface is bumpy (botryoidal texture) or vesicular. Piece is more or less tabular.
PHYSICAL CHARACTERISTICS OF AZURITE:
Color is azure, deep blue or pale blue if found in small crystals or crusts.
Luster is vitreous to dull depending on habit.
Transparency: Transparent if in thin crystals, otherwise translucent to opaque.
Crystal System is monoclinic; 2/m.
Crystal Habits crystals are irregular blades with wedge shaped terminations. Also, aggregate crusts and radiating, botryoidal, nodular and earthy masses.
Cleavage is good in one direction and fair in another.
Fracture is conchoidal and brittle.
Hardness is 3.5-4.
Specific Gravity is 3.7+ (heavier than average).
Streak is blue.
Associated Minerals are numerous and include malachite limonite, calcite, cerussite, quartz, chalcopyrite, native copper, cuprite, chrysocolla, aurichalcite, shattuckite, liroconite, connellite and other oxidized copper minerals.
Best Field Indicators are color, softness, crystal habits and associations.
THE PHYSICAL CHARACTERISTICS OF MALACHITE:
Color is banded light and dark green or (if crystalline), just dark green.
Luster is dull in massive forms and silky as crystals.
Transparency is opaque in massive form and translucent in crystalline forms.
Crystal System is monoclinic; 2/m.
Crystal Habitsin its massive forms are botryoidal, stalactitic or globular. Crystals are acicular or fibrous and form in tufts and encrustations. Frequently found as pseudomorphs of azurite.
Cleavage is good in one direction but rarely seen.
Fracture is conchoidal to splintery.
Hardness is 3.5-4.
Specific Gravity is 3.9+ (slightly heavy).
Streak is green.
Other Characteristics: Weakly effervesces in acid.
Associated Minerals include limonite, chalcopyrite, bornite, native copper, calcite, cuprite, azurite, chrysocolla and many rare copper minerals such as kolwezite, shattuckite, antlerite, brochantite, graemite, aurichalcite, sphaerocobaltite, atacamite, chalcophyllite, conichalcite, rosasite, chalcosiderite, clinoclase, cornetite, duftite, libethenite, liroconite, mixite and mottramite among others.
Best Field Indicators are color banding, softness, associations and reaction to acid.
PHYSICAL CHARACTERISTICS:
Color is usually a grass green but varies from white to green to greenish blue to light blue.
Luster is silky to fibrous or pearly on more massive specimens.
Transparency crystals are transparent to translucent.
Crystal System is orthorhombic; 2 2 2
Crystal Habits include radiating tufts of acicular crystals. also encrustations of fiberous or lamellar masses.
Hardness is 1 - 2
Specific Gravity is 3.6 - 4 (above average for non-metallic minerals)
Cleavage is perfect in one direction.
Fracture is uneven or fiberous.
Streak is white to pale shades that depend on color.
Associated Minerals include limonite, smithsonite, azurite, malachite, rosasite and calcite.
Other Characteristics: effervesceses easily in cold dilute hydrochloric acid.
Notable Occurrences include Bisbee, Arizona; Laurium, Greece; Tsumeb, Namibia and Mapimi, Durango, Mexico.
Best Field Indicators are crystal habits, color, associations, softness and reaction to acid
Common Name:Malachite
Group Name: Carbonates
Chemistry: Cu2(CO3)(OH)2, Copper Carbonate Hydroxide
PHYSICAL CHARACTERISTICS:
Color is banded light and dark green or (if crystalline), just dark green.
Luster is dull in massive forms and silky as crystals.
Transparency is opaque in massive form and translucent in crystalline forms.
Crystal System is monoclinic; 2/m.
Crystal Habitsin its massive forms are botryoidal, stalactitic or globular. Crystals are acicular or fibrous and form in tufts and encrustations. Frequently found as pseudomorphs of azurite.
Cleavage is good in one direction but rarely seen.
Fracture is conchoidal to splintery.
Hardness is 3.5-4.
Specific Gravity is 3.9+ (slightly heavy).
Streak is green.
Other Characteristics: Weakly effervesces in acid.
Associated Minerals include limonite, chalcopyrite, bornite, native copper, calcite, cuprite, azurite, chrysocolla and many rare copper minerals such as kolwezite, shattuckite, antlerite, brochantite, graemite, aurichalcite, sphaerocobaltite, atacamite, chalcophyllite, conichalcite, rosasite, chalcosiderite, clinoclase, cornetite, duftite, libethenite, liroconite, mixite and mottramite among others.
Best Field Indicators are color banding, softness, associations and reaction to acid.
Fracture: uneven
Hardness: 1 Talc
Luster: Silky
Occurrence: Azurite is unstable in open air with respect to malachite, and often is pseudomorphically replaced by malachite. The weathering process effect of the replacement of some the carbon dioxide (CO2) units with water (H2O). This change in the carbonate/hydroxide ratio of azurite into the 1-to-1 ratio of malachite:
2 Cu3(CO3)2(OH)2 + H2O ? 3 Cu2(CO3)(OH)2 + CO2
From the above equation the conversion of azurite into malachite is attributable to the low partial pressure of carbon dioxide in air. Azurite is also incompatible with aquatic media, such as salt-water aquariums.
Malachite often results from weathering of copper ores and is often found together with azurite (Cu3(CO3)2(OH)2), goethite, and calcite.
Rock Type: Sedimentary
Specific Gravity: 3.6-4
Streak: white
Texture: microcrystaline
Variety: While not a major ore of copper itself, azurite is a good surface indicator of the presence of weathered copper sulfide ores. It is usually found in association with the chemically very similar malachite, producing a striking color combination of deep blue and bright green that is strongly indicative of the presence of copper ores.
Malachite is a carbonate mineral normally known as "copper carbonate" with the formula CuCO3.Cu(OH)2. This green-colored mineral crystallizes in the monoclinic crystal system, and most often forms botryoidal, fibrous, or stalagmitic masses. Individual crystals are rare but do occur as slender to acicular prisms. Pseudomorphs after more tabular or blocky azurite crystals also occur.Collection
Suomynona Mineral CollectionAcquisition
Accession
2004.1Source or Donor
Suomynona Mineral CollectionAcquisition Method
DonationDimensions
Width
4 inDepth
2 inLength
5-5/16 inWeight
0.77 ozDimension Notes
Dimension taken at widest pointsLocation
Location
Container
RightDrawer
BottomShelf
Left, LeftWall
NorthBuilding
Founders RoomCategory
PermanentMoved By
Ray BlohmDate
February 20, 2012Location
Shelf
RightCabinet
Case # 7Room
Mentzer HallBuilding
Crater Rock MuseumCategory
Permanent
