THE MINERAL CONICHALCITE

Dims: 3"x1-1/2"x1"

Wt: 0.6 oz

Ojuela Mine, Mapimi, Durango, Mexico

Though a classic Mexican specimen as shown by the Limonite matrix, this Conichalcite crust is unusual due to the large size of its crystals. Most specimens don't have crystals large enough to achieve the sparkly sheen that this item has on its almost botryoidal form. The druse's color is a pale grass-green. I don't really like Mexican pieces that have Limonite matrices, but I LOVE botryoidal minerals, and in this case the crystal size compels me to make an exception.

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

Wt: 10.9 oz

Ojuela Mine, Mapimi, Durango, Mexico

Another Mexican mineral specimen, easily identified by its Limonite matrix, this Conichalcite piece has an gorgeous botryoidal crust that covers about 35% of its surface area. The yellowish grass-green of the mineral contrasts spectacularly with the red-brown of the Limonite base. The crust is very sparkly due to a druse of Calcite crystals that coat the Conichalcite. An extremely attractive item, this piece will add color to any collection.

Dims: 2.6" x 2.3" x 2.1"(6.6 x 5.8 x 5.3 cm)

Wt: 5.31 oz.(150.6 g)

Gold Hill Mine, Tooele County, Utah, U.S.A.

A grass-green crust of Conichalcite rests on this Utah specimen. It has no definite crystal form, a dull luster, and an indeterminate translucence. Its habit has botryoidal tendencies. This crust rests on a thick layer of halloysite, an aluminum silicate hydroxide and member of the kaolinite group. I believe that there may be some other copper phosphate minerals in this specimen, or maybe some chrysocolla, but I cannot be sure. The base rock looks like a pale brown shale or mudstone, and has veins of a bright green-blue mineral running through it for short distances. This is a very pretty and mysterious mineral specimen that I will have to study a bit.

Dims: 3.4" x 2.6" x 1.6"

Wt: 5.79 oz.(164.1 g)

Gold Hill Mine, Tooele County, Utah, U.S.A.

This specimen shows a thin bright green crust of Conichalcite on a matrix that shows both brown and pale blue coloration. The Conichalcite is in both a massive and a botryoidal form. It has no luster and no detectable transparence or translucence. The matrix that it rests upon appears to be made up of some type of shale or mudstone, but I cannot be certain. The blue colored material that is scattered throughout it is apparently a member of the kaolinite mineral group called halloysite.

Dims: 2.0" x 1.8" x 1.5"(5.1 x 4.6 x 4.0 cm)

Wt: 1.98 oz.(56.2 g)

Gold Hill Mine, Tooele County, Utah, U.S.A.

Though not showing much Conichalcite, this specimen is rather unusual. The visible Conichalcite has a bright, grass-green coloration, no luster, and no crystal form. It does seem, however, to have a definite transparence, which may simply be caused by the thinness of the crust that it has formed. This transparence is evident because one is able to see through the crust to the massive halloysite below! This white member of the kaolinite group has no form, no luster, and is very soft, with a soapy texture. The sparse host looks like a brown mudstone or sandstone.

Dims: 2.4" x 1.9" x 1.9" (6.1 x 4.8 x 4.8 cm)

Wt: 5.11 oz. (145.1 g)

Gold Hill Mine, Tooele County, Utah, U.S.A.

This specimen consists of a very thin coating of Conichalcite on a layer of halloysite, a kaolinitic mineral. The Conichalcite layer has a bright color that is a bit too yellow to be considered grass-green. It shows no crystal form and has no luster. I almost get the feeling that someone made a mixture of green and yellow food coloring, and dripped it onto areas of the halloysite. The halloysite itself is also amorphous and has a dull luster, though there is a very small spot that seems to be nearly polished, but I don't think intentionally so. It is soft enough to scratch with a fingernail, and it has a very pale blue coloration. The host rock has a rusty coloration and seems to be botryoidal in nature. I think that it is made up of goethite, though it reminds me a bit of bauxite. There are a few very small areas, however, that have a dark gray-black coloration and a shiny, almost metallic luster. Under 10-power magnification, they appear to be either hematite or cuprite, I cannot tell which (probably hematite). I like pieces like this, because there is the element of the unknown involved with them, and I think it is fun to try to figure out such little "mysteries".

Dims: 2.3" x 1.1" x 1.0" (5.8 x 2.8 x 2.5 cm)

Wt: 1.11 oz. (31.5 g)

Ojuela Mine, Mapimi, Durango, Mexico

This large thumbnail specimen consists of a thin crust of bright-green conichalcite that coats a portion of a goethite/limonite host rock. The crust shows many small but definite botryoidal formations, and is opaque and has a dull luster. It appears to sparkle, however, because the thin crust is mostly coated with tiny trigonal "dogtooth" calcite crystals. These crystals show almost no damage, are seemingly transparent, and have a bright, pearly-to-vitreous luster. These crystals are highly concentrated at one end of the crust, so as to completely obscure its visible botryoidal tendencies. Close examination with a loupe or magnifier shows a wonderful tiny world made up of round green balls and sharp, shiny spikes, but at least 30x magnification is recommended for the best effect.

Dims: 3.1" x 2.2" x 1.9" (7.9 x 5.6 x 4.8 cm)

Wt: 5.1 oz. (144.9 g)

Mapimi, Durango, Mexico

This small hand specmien consists of a thin but rather pervasive crust made up of scores of botryoidal Conichalcite nodules that partly covers a limonite and goethite host rock. These nodules are tiny, not exceeding 0.1" (3 mm) in diameter, but are generally in excellent condition, as only a few are visibly damaged. The crust is rather odd in the fact that its green color is exceptionally dark. Like many such specimens from this locality, the Conichalcite is mostly covered with a layer of colorless and transparent calcite that in some areas takes on a rhombohedral form. The calcite gives the normally dull Conichalcite a bright vitreous luster and a sparkle. The crust is to all intents and purposes opaque, and serves as the base for a few small Wulfenite blades, most of which are gathered in a small cluster (see the close-up image).

Dims: 3.1 x 1.9 x 1.4" (7.9 x 4.8 x 3.6 cm)

Wt: 2.42 oz. (68.5 g)

Mapimi, Durango, Mexico

Scores of tiny Conichalcite nodules form a crust that partly covers the limonite base of this specimen. These nodules do not exceed 0.1" (3 mm) in diameter and are generally in excellent condition due to the protective nature of the host rock on which they rest. Each nodule is made up of several nearly microscopic crystals that appear to have reasonably good orthorhombic form, given their intergrowth. The crystals have a grass-green coloration and a bright pearly luster, and are translucent.

Dims: 3.2 x 1.7 x 1.2" (8.1 x 4.3 x 3.1 cm)

Wt: 3.9 oz. (111 g)

Mapimi, Durango, Mexico

A thin crust of botryoidal Conichalcite rests on the goethite/limonite base of this specimen. This crust is made up of hundreds of tiny, round Conichalcite nodules that have a grass-green coloration and a dull, pearly-to-waxy luster. Its color appears darker and duller, however, due to the adjacent limonite base, and in most areas has a moderately bright sparkle due to thin crusts of transparent calcite that rests atop the Conichalcite. A few larger calcite crystals are wedged in a crevice under the crust, but these appear to be broken and incomplete.

Dims: 2.7 x 1.9 x 0.9" (6.9 x 4.8 x 2.3 cm)

Wt: 2.58 oz. (73.3 g)

Mapimi, Durango, Mexico

Several thin Conichalcite veins permeate the flat host rock of this piece, making a layered effect. One of the Conichalcite layers is completely exposed but is covered in crystalline calcite, so that one can only see its grass-green color. On the other side, it shows its orthorhombic form in the manner of almost microscopic, fibrous needles that have a silky luster. Both minerals extend through the powdery limonite host, and generally the calcite coats the Conichalcite.

Dims: 4.6 x 2.9 x 1.7" (11.7 x 7.4 x 4.4 cm)

Wt: 8.7 oz. (248 g)

Gold Hill, Tooele County, Utah, U.S.A.

Thin Conichalcite crusts partly cover the surface of this larger cabinet specimen. These crusts show no evidence of crystal form and have the grass-green color that is standard for this specie. The Conichalcite has a dull, matte luster and is opaque, and is partly covered by layers of a colorless mineral that may be calcite or smithsonite. The base rock on which it rests has some iron-oxide staining, but appears to consist primarily of calcite or another calcium mineral.

Dims:1.7x1.3x1.0" (4.3x3.3x2.5 cm)

Wt: 1.9oz. (53g)

Old Reliable Mine, Copper Creek, Pinal cty., Arizona

This specimen consists of a thin crust of green conichalcite microcrystals on a piece of matrix material. The crystals of conichalcite are so small that one cannot effectively study them, even with a loupe. There is no noticeable damage to this specimen.

Dims:4.7x3.3x1.4" (11.9x8.4x3.6 cm)

Wt: 12.0oz. (342g)

Gold Hill, Tooele cty., Utah

Tiny crystals and nodules of conichalcite are spread over much of the surface of the matrix of this specimen. On one side, a calcite fissure filling has a crevice filled with tiny crystals of conichalcite. These crystals are best viewed with a loupe. Overall, they impart a rich green color to this specimen. There is only minor damage to this piece, primarily to the calcite.

Dims:5.4x3.0x2.9" (13.7x7.6x7.4 cm)

Wt: 21.0oz. (596g)

Gold Hill, Tooele cty., Utah

The matrix of this specimen is embedded with tiny nodules of conichalcite, imparting a rich green color where it is concentrated. In small recesses in the matrix, crystals of conichalcite have formed. These crystals are tiny, and are best viewed with a loupe. There is only minor damage to this specimen.

Dims: 5.06x3.08x2.39" (12.85x7.82x6.07cm)

Wt: 17.92oz (508g)

Mina Ojuela, Mapimi, Mexico

A cavity in a brown rock has become coated with a druze of bright green conichalcite crystals. There are also a number of colorless, slightly translucent (nearly transparent) calcite crystals. The conichalcite crystals are a bright lime-sherbert green, and are organized as a crust of tiny balls of conicalcite crystals. These have a bright luster, and give the specimen a great deal of sparkle.

Dims: 2.95x2.22x1.36" (7.50x5.65x3.46cm)

Wt: 5.95oz (168.8g)

Gold Hill, Tooele County, Utah, USA

Scattered over two sides of a piece of semi-massive quartz are several patches of lime-green conichalcite. A loupe reveals that the crusts are comprised of botryoidal aggregates of conichalcite, which in places is so green that it may be transparent inside, although the appearance is simply translucent, with a dull luster.

Dims: 4.17x2.80x1.78" (10.59x7.12x4.52cm)

Wt: 11.99oz (340g)

Gold Hill, Tooele County, Utah, USA

This is a good hand specimen of conicalcite, among and beneath a druze of colorless quartz. The bright green of the conicalcite contrasts well against the white quartz and rusty colored limonite of the host rock. The inividual crystals of conicalcite are too small to be resolved by my loupe, although they occur in tiny balls and botryoidal crusts. All of the sparkle is due to quartz crystals, all of which appear to lie on their sides.

dims mm=131.66x97.70x59.14

wt g=994

Gold Hill, Tooele County, Utah, USA

A hefty chunk of brown rock is almost entirely coated with quartz, some of which has an unusual crystal habit. Many areas of the white quartz display a bright green coating of conichalcite, which shoes no crystal form even under a loupe, although some areas appear botryoidal. Much of the conichalcite has a layer of quartz crystals over it, giving it a bit of sparkle.