Name/Title
MalachiteEntry/Object ID
78.62.143Description
Chemical Composition: Cu2(CO3)(OH)2
Crystal System: Monoclinic System
Description: Common Name: Malachite
Chemistry: Cu2(CO3)(OH)2, Copper Carbonate Hydroxide
Group Name: Carbonates
Location: Katango, Congo
Descriptionh: Delmar described this specimen as a piece of malachite (Basic Green copper carbonate) from belgian congo, Africa.Colors:polished side shows smooth "bumpy" surface in greens. unpolished sides show layered green aad grey backing.
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.
Best Field Indicators are color banding, softness, associations and reaction to acid.
Fracture: conchoidal
Grain Size: Medium
Hardness: 3 Calcite
Luster: Silky
Occurrence: Malachite often results from weathering of copper ores and is often found together with azurite (Cu3(CO3)2(OH)2), goethite, and calcite. Except for its vibrant green color, the properties of malachite are similar to those of azurite and aggregates of the two minerals occur frequently together. Malachite is more common than azurite and is typically associated with copper deposits around limestones, the source of the carbonate.
Large quantities of malachite have been mined in the Urals. It is found in the Democratic Republic of Congo; Zambia; Tsumeb; Namibia; Russia; Mexico; Broken Hill, New South Wales; England; Lyon; and in the Southwestern United States especially in Arkansas and Arizona. In Israel, malachite is extensively mined at Timna valley, often called King Solomon's Mines although research has shown that the site was not in use during the 10th century.[3]. Archeological evidence indicates that the mineral has been mined and smelted at the site for over 3,000 years. Most of Timna's current production is also smelted, but the finest pieces are worked into silver jewelry
Pressure: Moderate
Rock Color: Medium
Rock Origin: Post-depositional
Rock Type: Sedimentary
Specific Gravity: 3.9
Streak: green
Texture: mircocrystaline
Variety: Many beautiful specimens of malachite contain special combinations with other minerals. Such combinations are some of the most colorful mineral assortments in the mineral world. They include such stunningly colorful minerals as dark blue azurite, sparkling black mottramite, baby blue chrysocolla, or rusty red limonite. So common is malachite that it is associated with almost every secondary copper mineral whether they are carbonate minerals or not. Malachite is found with many rare copper silicates, halides, phosphates, sulfates and carbonates such as duftite, libethenite, aurichalcite, sphaerocobaltite, kolwezite, shattuckite, atacamite, chalcophyllite, antlerite, conichalcite, rosasite, chalcosiderite, clinoclase, brochantite, graemite, liroconite, mixite and cornetite, to name a few.
Malachite has a mineral impostor called pseudomalachite. Pseudomalachite is a copper phosphate that has a massive crystal habit and color that are very similar to malachite's habit and color, although the two minerals have different structures. Pseudomalachite means "false malachite" in latin and is very rare compared to malachite.
Malachite is an impostor of its own. It frequently pseudomorphs the closely associated mineral azurite. A pseudomorph is a mineral specimen where the original mineral has been chemically replaced by another mineral, but the outward appearance is still retained. Pseudomorph means "false shape" in latin parlance. The transformation is fascinating and sometimes leaves a nearly perfect azurite crystal shape that is actually malachite. Often the transformation is incomplete and leaves a blue/green mineral specimen unlike any other. A gem trade name is used for ornamental stones with this combination called azur-malachite. See the azurite page for a more detailed discussion of the transformation.Collection
Delmar Smith Mineral CollectionAcquisition
Accession
78.62Source or Donor
Delmar Smith Mineral CollectionAcquisition Method
DonationDimensions
Dimension Notes
Dimension taken at widest pointsLocation
Location
Shelf
top left center, top left centerWall
eastRoom
Minerals, Shells & Glass, Frieda Smith HallBuilding
Crater Rock MuseumCategory
PermanentMoved By
Catherine BoydDate
August 21, 2009Location
Container
CenterDrawer
LeftShelf
Top, TopWall
east wallRoom
Frieda Smith HallBuilding
Crater Rock MuseumCategory
PermanentMoved By
Catherine BoydDate
August 21, 2009Location
Shelf
RightCabinet
Case # 7Room
Mentzer HallBuilding
Crater Rock MuseumCategory
Permanent
