Rosasite
Current inventory:  0 gems
 

  
Rosasite is named after its discovery locality, the Rosas Mine, Sulcis, Sardinia, Italy.

Discovered in 1908;   IMA status: Valid (pre-IMA; Grandfathered)

Chemistry

Chemical Formula:

Cu,Zn₂(CO₃)(OH)₂

Copper Zinc Carbonate Hydroxide

Molecular Weight:

222.04 gm

Composition:

Zinc

14.72 %

Zn

18.33 %

ZnO

Copper

42.93 %

Cu

53.74 %

CuO

Hydrogen

0.91 %

H

8.11 %

H₂O

Carbon

5.41 %

C

19.82 %

CO₂

Oxygen

36.03 %

O

100.00 %

100.00 %

= TOTAL OXIDE

Classification

Mineral Classification:

Carbonates

Strunz 8th Ed. ID:

5/C.01-80

Nickel-Strunz 10th Ed. ID:

5.BA.10

5 : CARBONATES (NITRATES)
B : Carbonates with additional anions, without H₂O
A : With Cu, Co, Ni, Zn, Mg, Mn

Related to:

Rosasite Group

Varieties:

Nickeloan Rosasite

Synonyms:

Parauricalcite-I

Crystal Data

Crystallography:

Monoclinic - Prismatic

Crystal Habit:

Crystals are acicular, to 0.5 mm; in radial or divergent sprays or globular; compact mammillary to botryoidal crusts and masses, typically fibrous and with warty surfaces.

Twinning:

On {100}

Physical Properties

Cleavage:

Distinct/Good in two directions at right angles.

Fracture:

Splintery - Thin, elongated fractures produced by intersecting good cleavages or partings.

Tenacity:

Brittle

Moh's Hardness:

4.5

Density:

4.00 - 4.20 (g/cm³)

Luminescence:

None

Radioactivity:

Not Radioactive

Other:

Soluble in acids

Optical Properties

Color:

Blue, Blue-Green to Green, sky-Blue; Colorless to light blue in transmitted light.

Transparency:

Translucent

Luster:

Vitreous, Silky

Refractive Index:

1.672 - 1.831  Biaxial ( - )

Birefringence:

0.139 - 0.140

Dispersion:

Strong; r > v

Pleochroism:

Strong; X = pale emerald-green; Z = dark emerald-green

Occurances

Geological Setting:

An uncommon secondary mineral in the oxidized zone of Cu–Zn-bearing deposits, typically formed by zinc-bearing solutions on primary copper minerals; may be of post-mine origin.

Common Associations:

Malachite, Aurichalcite, Smithsonite, Cerussite, Hydrozincite, Hemimorphite

Common Impurities:

Mg, Fe

Type Locality:

Rosas Mine, Narcao, Carbonia-Iglesias Province, Sardinia, Italy

Year Discovered:

1908

View mineral photos:

Rosasite Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Rosasite forms in the oxidation zones of zinc-copper deposits and typically found as crusts and botryoidal masses or nodules. Crystals are an attractive bluish-green and fibrous. Because of this, gems are rare and are usually opaque or translucent at best but still very attractive because of the bright color and pearly, fibrous structure.

Rosasite is found in a number of localities worldwide including the type locality of Rosas mine, Sulcis, Sardinia, Italy. At a number of places in England, such as Caldbeck Fells, Cumbria, and mines in Cornwall. Fine examples from Tsumeb, Namibia. In the USA, from the Kelly mine, Magdalena, Socorro County, New Mexico; fine specimens from the Silver Bill mine, Gleeson, and at Bisbee, Cochise County, in the 79 mine, Gila County, and a number of other places in Arizona; from the Mohawk mine, San Bernardino County, California; at Leadville, Lake County, Colorado; from Majuba Hill, Pershing County, Nevada; in the Hidden Treasure mine, Ophir district, Tooele County, Utah. Abundant specimens from the Ojuela mine, Mapimí, Durango, Mexico. In small amounts from additional localities.
 

  
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