ATACAMITE
Specimen ata-4

Dims: 2-3/4" x 2-1/2" x 1-3/8"

Wt: 6 oz

Copaipo, Chile

This rare, dark-green copper chloride mineral is heavily dusted in a miroscopic crystal form over a thin crust of Chrysocolla on the host rock. Its dark-green color is its best field mark, and is so dark in this mossy mass as to appear almost black in some areas. Being a chloride, this mineral is very soluble in water, and being a copper mineral, it is poisonous, so it would be best to display such a piece behind glass, away from hungry organisms that don't know any better.

Dims: 3-1/2" x 2-1/2" x 1"

Wt: 6.3 oz

Copaipo, Chile

This flat, tabular specimen has a generous dusting of Atacamite on both sides of it, on top of a thin coating of Chrysocolla. The crystals are microscopic and needle-like, radiating in tiny sprays off of many tightly-grouped points. It is water-soluble and poisonous, so one must keep it dry and away from small children and animals. This specimen was found near the Atacama Desert in Chile, whence this mineral got its name.

Dims: 3" x 1-1/2" x 3/4"

Wt: 1.36 oz

Lafarola Mine, Copiapo, Chile

This Atacamite specimen actually reminds me a bit of dioptase, with its intense green coloration and its chrysocolla base. There are hundreds of needle crystals coating one side of the flat, tabular piece, along with a few tiny, botryoidal chrysocolla formations. The Atacamite crystals are all a deep, deep green,measure 1/8" in length, maximum, and have a vitreous luster. The reverse of the specimen shows several flat radiating clusters of Atacamite that grew in a very narrow crevice that the specimen covered.

Dims: 2.8" x 2.4" x 1.4" (7.1 x 6.1 x 3.6 cm)

Wt: 6.28 oz. (178.0 g)

Copiapo, Chile

The host rock of this specimen is partially coated with a thin layer of bladed Atacamite crystals. They are flattened against the surface of the host, so that individual crystals cannot be studied clearly, but they have definite form and their radiating habit makes small "sunburst" designs in the crust. They have the deep green color and vitreous luster that are characteristic of this mineral, but are pressed too deeply into the host to determine their translucence or transparence. The host rock appears to have a concentration of iron in it, and has several black spots on it that make me think of decayed azurite, but I am not sure of either one's composition.

Dims: 2.5" x 1.7" x 0.9" (6.4 x 4.3 x 2.3 cm)

Wt: 1.83 oz. (52.1 g)

La Farola Mine, Cerpp Pintada, Region 3, Chile

This small hand specimen consists of several round, flat, and radiating clusters of acicular Atacamite crystals on a thin slab of host rock. These clusters are in excellent condition, showing very little discernable damage, and attain diameters of 0.4" (1.0 cm). Their crystals are mostly intergrown, so studying their slender orthorhombic form is very difficult. All have a bright vitreous luster and a green color that is so dark that it is difficult to convey through our images. The crystals appear to be transparent and clear, though this too is difficult to study. The clusters rest on a thin, pale gray layer of partly-decayed copper-bearing minerals (I cannot define them further) that partly coats the base rock.

Dims: 2.5 x 1.7 x 1.1" (6.4 x 4.3 x 2.8 cm)

Wt: 2.32 oz. (65.5 g)

La Farola Mine, Cerpp Pintada, Region 3, Chile

Scores of tiny orthorhombic Atacamite blades cover part of the iron-rich host rock of this small specimen. Some of these crystals achieve visible lengths of 5 or 6 mm, but the majority are half that length or less. They are generally in good condition, though there are a few small areas of noticeable damage to the crust that they form. All have a deep green coloration and a bright vitreous luster. While individual crystals are transparent and quite clear, most of these are so heavily intergrown that their clusters show only a dim translucence. Interestingly, some of the crystals have grown parallel to their host rock, whereas the rest grow outwards in almost radial sprays. There is another, smaller crust of the "parallel-growth" crystals on the side of the piece that is opposite the large crust, part of which is still buried in the host rock.

Dims: 3.6 x 1.9 x 1.5" (9.2 x 4.8 x 3.7 cm)

Wt: 4.3 oz. (122 g)

Copiapo, Chile

This lovely hand specimen consists of dozens of intergrown Atacamite clusters that rest on a dull brown base rock. Each cluster is made up of several radiating Atacamite crystals that are generally in excellent condition (a few clusters on one face of the base rock are crushed) and reach 0.3" (8 mm) in length. They are the best-quality crystals of Atacamite that I have yet seen, and are quite easy to study- their orthorhombic prismatic form is excellent, and so thin as to appear nearly bladed or spiky in some cases. All have the classic, deep forest-green color and vitreous luster that are standard for this mineral, and even with their deep color, they are still transparent and noticeably clear. A small amount of what may be chrysocolla coats small portions of the base rock.

Dims: 1.0 x 0.8 x 0.4" (2.4 x 2.0 x 0.9 cm)

Wt: 2 g w/ foam base

Mina La Farola, Copiapo, Chile

A thin crust of crystalline Atacamite makes up this thumbnail specimen. The crystals that make up the crust are generally in very good condition and reach lengths of 0.2" (5 mm). The slender, spiky crystals have good orthorhombic form and show the classic deep green color and bright vitreous luster. As the crust has been removed cleanly from its base, there is no other material present. It is hot-glued onto a foam base that fits into a plastic specimen box.

Dims: 2.5 x 0.9 x 0.5" (6.3 x 2.3 x 1.4 cm)

Wt: 0.7 oz. (20 g)

Esperanza Mine, Provincia Copiapo, Region 3, Chile

Many intergrown Atacamite spikes lay against the green-brown base of this hand specimen. These spikes appear to be in good condition, though some damage is evident, and though they formed in a crevice, they appear to have good orthorhombic form. All have the classic deep forest-green color and vitreous luster of their specie, and are likely more translucent than transparent. They rest on a bed of massive chrysocolla that coats the base rock.

Dims: 3.8 x 3.5 x 1.0" (9.7 x 8.8 x 2.5 cm)

Wt: 7.9 oz. (225 g)

Mina La Farola, Sierra Las Pintados, Region III, Chile

Sprays of radiating, somewhat compact Atacamite rest on the flat gray base of this cabinet specimen. These sprays are made up of scores of compact blades that reach lengths of 0.5" (1.3 cm) and are in very good condition, though some breakage is visible. Though they are rather difficult to study individually, they appear to have good orthorhombic form. All have the standard deep green color and vitreous luster of the specie, and some are likely to be dimly transparent. The Atacamite sprays are accompanied by tiny olivenite nodules and possibly some nantokite (a copper chloride mineral)- all of these rest on a thin chrysocolla crust which covers the base rock.

Dims: 3.0 x 1.6 x 0.9" (7.6 x 4.0 x 2.2 cm)

Wt: 2.6 oz. (73 g) w/ base

La Farola Mine, Cerpp Pintada, Region III, Chile

Several compact, radial Atacamite aggregates rest on the base rock of this cabinet specimen. These aggregates consist of tightly intergrown crystals that do not exceed 0.3" (8 mm) in length and are generally in very good condition. Though heavily intergrown, their orthorhombic form appears to be good. All have the standard dark green color and vitreous luster of the specie. A thin layer of powdery, pale blue, botryoidal chrysocolla seems to separate the aggregates from the base rock, which is hot-glued to an acrylic base.

Dims: 2.2 x 1.4 x 0.5" (5.6 x 3.6 x 1.3 cm)

Wt: 1.2 oz. (34 g) w/ base

La Farola Mine, Cerpp Pintada, Region III, Chile

Three sprays of acicular Atacamite rest on this specimen. Two are incomplete, resting on the edges of the base rock, but all contain crystals that are in very good condition. They do not exceed 0.3" in length and have the standard dark green color and vitreous luster. A thin dusting of what may be chrysocolla lays between them and the base rock, which is affixed to an acrylic base with hot glue.

Dims: 2.8 x 1.4 x 0.8" (7.2 x 3.6 x 2.1 cm)

Wt: 2.3 oz. (66 g)

La Farola Mine, Cerpp Pintada, Region III, Chile

Several small acicular Atacamite sprays rest on the base rock of this small cabinet piece. All are complete, but only two are very well-formed. The Atacamite blades that they contain do not exceed 0.2" in length and are generally well-formed, though intergrown. Their dark green color and vitreous luster are standard for their specie. The base rock is coated with layers of various secondary copper minerals, such as chrysocolla. A flat, acrylic base is included.

Dims: 2.79x2.46x1.17in (7.08x6.24x2.98cm)

Wt: 7.94oz (225g)

Mina La Farola, Copiopo, Chile

While there are a dozen small clusters of atacamite on this specimen, it is dominated by a single large spray of crystals laying flat against the specimen. The radial crystal growth is apparent, and a loupe reveals that many of the individual crystals are beautifully transparent with a deep green color and vitreous luster.