THE MINERAL OLIVENITE

  • Chemistry: Cu2AsO4(OH), Copper Arsenate Hydroxide
  • Class: Phosphates
  • Uses: As mineral specimens and minor ore of copper.
  • Specimens
Olivenite is a rare secondary copper mineral that is noted for its deep olive green color, hence the name. It is found in deeply weathered, highly concentrated copper sulfide ore bodies. Olivenite is isostructural with the minerals libethenite, Cu2PO4(OH) and adamite, Zn2AsO4(OH). This means that they share the same symmetry and crystal shapes. Olivenite's olive green color and bright luster make it a popular mineral specimen.

It has a rare but notable second habit: it can also form fibrous masses and sheets, and in this form it appears white, even much like a sheet of paper. This variety of olivenite is called leucochalcite. It is similar in form to "mountain leather" (a variety of actinolite).

PHYSICAL CHARACTERISTICS:

  • Color is dark olive green.
  • Luster is resinous to nearly adamantine.
  • Transparency: Specimens are translucent to almost opaque.
  • Crystal System is orthorhombic 2/m2/m2/m
  • Crystal Habits include crystals that are diamond-shaped, often acicular, prisms that are terminated by a dome with triangular faces. Can form feniform masses similar to wavellite's typical habit. Also as tiny crystalline druzes, fiberous masses, nodules and crusts.
  • Cleavage is poor in two directions, but rarely noticed.
  • Fracture is conchoidal.
  • Hardness is 3
  • Specific Gravity is approximately 3.9 - 4.4 (above average to heavy for translucent minerals)
  • Streak is olive green.
  • Associated Minerals are malachite, libethenite, Clinoclase, limonite, adamite, agardite and other secondary copper ore minerals.
  • Other Characteristics: Soluable in hydrochloric acid.
  • Notable Occurrences: Cornwall, England; Nevada, USA and Tsumeb, Nambia.
  • Best Field Indicators are color, habits, soluability in hydrochloric acid, associations, locallities and density.
OLIVENITE specimens:
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OLIVENITE specimen olv-1
$ 23.00
Dims: 2.25" x 1.81" x 1.5"(5.7 x 4.6 x 3.8 cm)
Wt: 3.05 oz.(86.6 g)
Majuba Hill Mine, Pershing County, Nevada, U.S.A.
Many small, thin, prismatic crystals of Olivenite lay on the quartzite host rock of this specimen. They are very small(less than 5 mm in length) and have a dark green color. Each crystal has the shape of a knife blade and has a pearly luster. There is considerable damage to several of the crystals, with parts of them having been broken off. There are a few small patches of a bright green crust that could be turquoise, variscite, or conichalcite, it is difficult to tell which- I would guess variscite. Three distinct and separate clusters of these little crystals are visible on the matrix rock, which shows some heavy fracturing.
no photo
olv-1 ($ 23.00)
Majuba Hill Mine, Pershing County, Nevada, U.S.A.
OLIVENITE specimen olv-2
$ 90.00
Dims: 2.4" x 2.4" x 2.0"(6.1 x 6.1 x 5.1 cm)
Wt: 3.50 oz.(99.3 g)
Majuba Hill Mine, Pershing County, Nevada, U.S.A.
Several dozen dark olive green Olivenite crystals infest what I believe to be a Goethite matrix on this specimen. These crystals almost remind me of vivianite, with their curved form and pearly to vitreous luster. The crystals dull translucence is difficult to see because the crystals do not tend to grow outwards from the host rock. They do not exceed 1/4"(6 mm) in length, and most of them inhabit rough depressions in the host rock and some crevices along the specimen's edge.
no photo
olv-2 ($ 90.00)
Majuba Hill Mine, Pershing County, Nevada, U.S.A.
OLIVENITE specimen olv-3
$ 53.00
Dims: 2.2" x 1.6" x 1.3"(5.6 x 4.1 x 3.3 cm)
Wt: 1.93 oz.(54.9 g)
Majuba Hill Mine, Pershing County, Nevada, U.S.A.
Though small, this specimen contains quite a substantial amount of Olivenite in depressions in the host rock. One large depression is completely coated with the dark olive-green crystals, and contains several deep crevices which are likewise coated. The crystals have a pearly to vitreous luster due to heavy striations on them and occur as curved, bladed crystals. A few spots also have crystals radiating from central points in an almost acicular manner. These crystals do not exceed 1/8"(4mm) in length. They have a dull translucence, but due to their secluded nature it is difficult to see. There is another, smaller hollow opposite the larger one on the specimen that is likewise coated with crystals. Along the surface of the host rock(which is made up of a variety of materials) there are pale green areas that surround the crystals, and may actually be made up of decayed Olivenite.
no photo
olv-3 ($ 53.00)
Majuba Hill Mine, Pershing County, Nevada, U.S.A.
OLIVENITE specimen olv-4
$ 30.00
Dims: 2.3 x 2.0 x 1.4" (5.8 x 5.1 x 3.5 cm)
Wt: 3.2 oz. (91 g)
Majuba Hill Mine, Pershing County, Nevada, U.S.A.
Dozens of intergrown Olivenite crystals rest on the rusty host rock of this hand specimen. These crystals do not exceed 0.2" (5 mm) in length and are generally in very good condition, as they formed inside hollows within the host. Their orthorhombic bladed form is mostly intergrown, but where they are isolated, the crystals occur as aggregates of several thin blades. All have a deep olive-green color that appears nearly black in some areas and a bright pearly luster. Most of the crystals are only dimly translucent, and some appear to be opaque.
no photo
olv-4 ($ 30.00)
Majuba Hill Mine, Pershing County, Nevada, U.S.A.
OLIVENITE specimen olv-5
$ 30.00
Dims: 2.5 x 1.6 x 1.5" (6.3 x 4.2 x 3.8 cm)
Wt: 3.6 oz. (103 g)
Majuba Hill Mine, Pershing County, Nevada, U.S.A.
Scores of tiny, spiky Olivenite needles rest on the rusty gray base of this hand specimen. These crystals do not generally exceed 0.1" (3 mm) in length and are in excellent condition, showing almost no damage. Their orthorhombic form is somewhat disseminated but still definite. All have a deep, forest-green coloration and a bright pearly luster, and are dimly transparent.
no photo
olv-5 ($ 30.00)
Majuba Hill Mine, Pershing County, Nevada, U.S.A.
OLIVENITE specimen olv-6
$ 40.00
Dims: 0.9 x 0.8 x 0.7" (2.4 x 2.0 x 1.8 cm)
Wt: 14 g w/ specimen box
Majuba Hill Mine, Pershing County, Nevada, U.S.A.
This thumbnail specimen consists of a dark brown base rock that is partly coated with scores of fine Olivenite needles. These needles appear to be in very good condition and reach lengths of about 0.3" (8 mm). All appear to have good orthorhombic form and the classic olive-green color and pearly luster. The needles appear to be transparent and clear. The base rock appears to contain some limonite and is hot-glued into a plastic specimen box.
no photo
olv-6 ($ 40.00)
Majuba Hill Mine, Pershing County, Nevada, U.S.A.
OLIVENITE specimen olv-8
$ 25.00
Dims: 1.9 x 1.5 x 1.0" (4.7 x 3.8 x 2.6 cm)
Wt: 1.4 oz. (40 g)
Majuba Hill Mine, Pershing County, Nevada, U.S.A.
Scores of tiny Olivenite blades rest on the rusty brown host rock of this hand specimen. The blades do not exceed 0.1" (3 mm) in length or width, but they are in excellent condition, as they tend to line protective hollows in the rock. Their orthorhombic form is quite good, though many appear to be slightly warped, and all have the greenish-black color and nearly adamantine luster that are common for the specie.
no photo
olv-8 ($ 25.00)
Majuba Hill Mine, Pershing County, Nevada, U.S.A.
OLIVENITE specimen olv-7
$ 36.00
Dims: 1.6 x 1.1 x 0.8" (4.2 x 2.7 x 2.1 cm)
Wt: 21 g
Wheal Gorland, Cornwall, England
A few small druses of tiny Olivenite crystals line pockets in the quartz base of this large thumbnail specimen. These crystals do not exceed 0.1" (3 mm) in length but are in excellent condition due to their small size and their protective surroundings. The crystals are a bit too small and tightly arranged for one to easily study their orthorhombic prismatic forms with a loupe, but their form seems good, anyway. All have the standard dark olive-green color and vitreous luster of the specie, and all are transparent and dimly to moderately clear. A small amount of what appears to be massive, pale green malachite is also present.
no photo
olv-7 ($ 36.00)
Wheal Gorland, Cornwall, England
OLIVENITE specimen olv-10
$ 39.00
Dims: 2.1 x 1.5 x 1.4" (5.3 x 3.7 x 3.5 cm)
Wt: 2.1 oz. (60 g)
New Cornelia Mine, Ajo, Pima County, Arizona, U.S.A.
Several veins of massive and crystalline Olivenite permeate the rusty-brown matrix of this hand specimen. In some areas, these veins have formed clusters of tightly-packed fibrous crystals that do not exceed 0.1" (3 mm) in length. Though they are difficult to study even with a loupe, they appear to be in good condition and have good orthorhombic form. All have the deep forest-green color and pearly to vitreous luster that are common for the specie, and individual crystals appear to be transparent. The massive material has the same color and luster, but does not show any definable crystal form.
no photo
olv-10 ($ 39.00)
New Cornelia Mine, Ajo, Pima County, Arizona, U.S.A.
OLIVENITE specimen olv-9
$ 37.50
Dims: 1.5 x 1.1 x 1.0" (3.9 x 2.7 x 2.5 cm)
Wt: 0.7 oz. (20 g)
Majuba Hill Mine, Pershing County, Nevada, U.S.A.
At least 15 Olivenite blades rest on the rusty base of this small hand specimen. These crystals are generally in very good condition, showing little damage, and reach lengths of nearly 0.3" (8 mm). All have a reasonably good orthorhombic form, given their intergrowth. Their green color is so dark as to appear essentially black and opaque, and all have a resinous luster. The host rock strongly resembles goethite or limonite.
no photo
olv-9 ($ 37.50)
Majuba Hill Mine, Pershing County, Nevada, U.S.A.
OLIVENITE specimen olv-11
$ 25.00
Dims: 2.5 x 1.6 x 1.0" (6.3 x 4.1 x 2.6 cm)
Wt: 2.3 oz. (65 g)
New Cornelia Mine, Ajo, Pima County, Arizona, U.S.A.
Countless tiny Olivenite crystals rest in a small hollow in the shale base of this hand specimen. These crystals measure less than 1 mm in length, so at least a loupe is needed to study them. Those within the protective hollow are in very good condition and likely have good orthorhombic form. All have a deep green color and a pearly luster, and are transparent.
no photo
olv-11 ($ 25.00)
New Cornelia Mine, Ajo, Pima County, Arizona, U.S.A.
 

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