MIMETITE
Specimen mim-18

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

Wt: 12 g

Tsumeb, Namibia

This is the only Mimetite specimen that I know of in our selection that is solely Mimetite. It consists of a cluster of crystalline aggregates, each about 1/4 inch long, that are colored a dirty orange-yellow. The visible crystal faces have a bright, sub-adamantine luster. For $19, you are getting a fine example of Mimetite for a paltry sum.

Dims: 7/8" x 3/4" x 9/16"

Wt: approx. 7g

Kellogg, Idaho, U.S.A.

This specimen of Mimetite has rough hexagonal prismatic crystals and basal terminations that look a lot like those of pyromorphite, a closely related lead chlorophosphate mineral. There are dozens of crystals on the specimen, which seems to be composed of a crust of this mineral that separated from its host rock. The largest is less than 1/4 inch long and 1/8 inch in diameter. All crystals have a dull golden color, and pleasant pearly luster.

Dims: 2.3" x 1.9" x 1.4"(5.8 x 4.8 x 3.6 cm)

Wt: 3.52 oz(99.9 g.)

Aguiles Serdan, Chihuahua, Mexico

This specimen contains a lot of Mimetite! It is virtually covered with sparkly nodules of the mineral, colored a dull brown. The nodules don't get larger than 1/3"(about 5 mm) in diameter. They all sparkle with the presence of small crystals. These crystals actually increase in size, with some of them so large(1/8" or 3mm) that nodules will not form. These larger crystals are colorless and transparent, whereas the nodules are merely translucent. They have a vitreous luster and good crystal form, but their small size and concentration prevents me from discerning their habit. The host rock that these nodules and crystals rest on appears to be a dark brown variety of limonite; only about 20-25% of its surface area is visible.

Dims: 1.7" x 1.4" x 1.0"(4.3 x 3.6 x 2.5 cm)

Wt: 1.10 oz(31.4 g.)

Aguiles Serdan, Chihuahua, Mexico

For its size, this specimen contains an impressive number of Mimetite crystals- it is likely over 70% Mimetite by weight. It occurs as radidating prisms and aggregates, some of which take on a plumose form. All are a dull golden color and have a vitreous luster and dim translucence. The largest aggregates measure 0.4"(1.0 cm) long, and anywhere from 0.2 - 0.3"(5 - 8 mm) in width. One of these larger aggregates has several tiny, transparent crystals growing off of it- they are visible, but a loupe or magnifier makes viewing much easier. The crystals create a crust that holds them together, but there is a sizable chunk of brown limonite that represents the host rock. There are some tiny, transparent crystals on some of the Mimetites that resemble calcites to some degree, but also remind me of hemimorphite. I really can't tell which they are, but my guess is calcite. It is a wonderful piece to examine under magnification!

Dims: 1.9" x 1.9" x 1.6"(4.8 x 4.8 x 1.6 cm)

Wt: 3.51 oz(99.6 g)

Santa Eulalia, Chihuahua, Mexico

A large nodule of white, crystalline calcite covered with a cluster of scores of Mimetite crystals constitutes this Mexican specimen. The Mimetites occur in a warped but definable hexagonal prismatic form and are often hollow, seeming to have an almost hoppered appearance. They reach a maximum length of about 0.4"(1.0 cm), have a deep yellow-green color and a pearly luster, and are translucent. Some white, rhombohedral calcite crystals are visible between crystals, and a few small colorless, transparent crystals rest on top of the uppermost crystals on the nodule. There are small spots of damage on the cluster, but its general condition is excellent. It is one of the few Mimetite specimens that I have seen with good crystal form.

Dims: 2.6" x 1.8" x 1.3" (6.6 x 4.6 x 3.3 cm)

Wt: 2.71 oz (76.8 g)

Chihuahua, Mexico

The Mimetite on this specimen occurs in a botryoidal form that has a silky luster that is almost reminiscent of smithsonite. The nodules are small, not exceeding 0.2" (5 mm) in diameter, and they have a yellow color that is somewhat dulled by the inclusion or staining of Limonite. The nodules are translucent and rest on a base of dark brown limonite. Among the yellow nodules are two or three distinguishable crystal faces. They have the same color and a rather dull pearly luster, so I am pretty certain that they are also composed of Mimetite.

Dims: 4.8" x 3.0" x 1.9" (12.2 x 7.6 x 4.8 cm)

Wt: 1 lb., 0.9 oz (479 g)

Santa Eulalia, Chihuahua, Mexico

Though occurring in small crystals, there is an impressive amount of Mimetite on the limonite host rock of this specimen. Individual crystals do not generally exceed 3 mm in length, and many measure less than 1 mm. There are larger formations on the specimen; these consist of aggregates of smaller crystals that take on either a plumose or a botryoidal form. Whatever its form, it all has a dull yellow coloration, is translucent, and has a luster that ranges from waxy to pearly. The limonite host rock, though rather heavily weathered, shows some definite layering in which are several small hollows; these hollows tend to contain more crystals or aggregates of Mimetite. It seems to pervade the entire host rock.

Dims: 2.1" x 1.9" x 1.1" (5.3 x 4.8 x 2.8 cm)

Wt: 1.50 oz. (42.6 g)

San Pedro Corralitos, Chihuahua, Mexico

A very attractive specimen, this piece consists of a goethite/limonite base on which rest dozens of round, botryoidal Mimetite globules. They range in diameter from less than one millimeter to 0.2" (0.5 cm), and are in excellent condition, showing almost no damage. The clusters have a dull yellow coloration and a dull, silky luster, and are translucent. Some of the larger globules rest on what appear to be small clusters of intergrown adamite crystals- I cannot be certain, but that is what I think they are! These crystals have a pearly luster, a pale pink-violet coloration, and are transparent and relatively clear, though one cannot see much of them. They only add to the beautiful specimen, making it also a bit unusual and intriguing.

Dims: 1.9" x 1.6" x 0.9" (4.8 x 4.18 x 2.3 cm)

Wt: 1.28 oz. (36.4 g)

San Pedro Corralitos, Chihuahua, Mexico

Like the previous specimen in our selection, this Mimetite piece comes from the mines of San Pedro Corralitos in Mexico, where some extremely beautiful Mimetites are found. This particular specimen consists of a thin crust if limonite which is mostly coated with the lead chloroarsenate mineral. The Mimetite is in a botryoidal form, showing beautiful, bulbous nodules that have very little damage. The largest measurable nodule has a diameter of nearly 0.3" (0.8 cm), but it is so intergrown with several others that the cluster could be thought of as a single entity. The nodules have a lovely, subtle velvety luster and their color ranges from a pale yellow to a deep yellow-gold. They are definitely translucent, and a few of the smaller ones are stained with limonite from the crust. It is a very beautiful specimen.

Dims: 3.0" x 2.6" x 1.5" (7.6 x 6.6 x 3.8 cm)

Wt: 11.0 oz. (311 g)

Aguiles Serdan, Chihuahua, Mexico

This hand specimen intrigues me a bit. At first, I thought that the crysals that are so obvious were actually made of Mimetite. However, some close examination and a tiny drop of hydrochloric acid caused me to change my mind. The Mimetite of this specimen really acts as a base off of which a thin druse of tiny calcite crytstals grows. The Mimetite is massive and has an obviously botryoidal form. It shows a dull yellow-orange color with a hint of brown, has a dull pearly-to-waxy luster, and is dimly translucent. The calcites that cover it are very small, not exceeding a few millimeters in a

Dims: 2.5" x 2.0" x 1.7" (6.4 x 5.1 x 4.3 cm)

Wt: 5.53 oz. (157.0 g)

Aguiles Serdan, Chihuahua, Mexico

This small hand specimen consists of a cluster of botryoidal Mimetite nodules that grow off of a dark brown host rock. These nodules are in excellent condition, showing almost no damage. They have a very dull yellow color that is almost brown and a dull, satiny luster. All are only dimly translucent, even in halogen light. The host rock on which they rest is made up of limonite and is permeated with hollows that contain small rhombohedral calcite crystals and more botryoidal Mimetite. The calcites have excellent form and are colorless, transparent, and quite clear.

Dims: 2.5 x 1.6 x 0.7" (6.4 x 4.1 x 1.8 cm)

Wt: 2.14 oz. (60.7 g)

Santa Eulalia, Chihuahua, Mexico

Hundreds of small, radiating Mimetite crystals are clustered together on the limonite host rock of this Mexican specimen. The crystals are generally in excellent condition, showing very little damage, and do not exceed 3 mm in length or 2 mm in diameter. On one side of the specimen, they show a color that ranges from pale yellow in the smallest crystals to a dull gold in the larger ones and a pearly luster. The other side of the specimen has crystals that show a dull brown coloration and a dull luster due to the fact that they are covered with a thin layer of limonite. All have warped but moderately good hexagonal prismatic form and tend to be gathered in "sprays", in which the crystals radiate outward from central points. There are a few clusters of heavily intergrown rhombohedral calcites resting among the limonite-coated Mimetites- they have the same brown coloration but show a bright vitreous luster. These calcites cover almost half of the face on which they rest.

Dims: 2.3 x 1.4 x 1.2" (5.8 x 3.6 x 3.0 cm)

Wt: 2.3 oz. (65.2 g)

El Potosi Mine, Chihuahua, Mexico

This specimen consists of scores of small Mimetite nodules that rest on a goehtite and limonite base rock. The nodules are generally in excellent condition, as there is very little damage. These formations range in diameter from less than 1 mm to 0.3" (8 mm) and are mostly malformed- several of the larger formations are flattened so as to have elliptical outlines when viewed along two of their axes. A few of the smaller nodules are clustered together in an almost botryoidal formation. All have a rather dull pale-brown coloration and a subtle sparkly luster, and are essentially opaque. The host rock contains many small crevices and hollows whicn are lined with more of these nodules and a few very tiny crystals. The specimen is affixed to an oblong acrylic base with an adhesive put

Dims: 2.2 x 1.6 x 0.8" (5.5 x 4.1 x 2.0 cm)

Wt: 1.6 oz. (44 g) w/ base

Santa Eulalia, Chihuahua, Mexico

Scores of small Mimetite prisms coat parts of this oddly-shaped cabinet piece. These crystals are in excellent condition, showing almost no damage, and have very good hexagonal prismatic "barrel" form. Their color ranges from pale yellow to dull green to rust-red and their luster is subadamantine. They reach lengths of about 0.1" (3 mm). The Mimetites partly cover several calcite rhombohedrons that also rest on the sparse limonite base; the piece is affixed to an acrylic base with a hot glue.

Dims:3.3x1.1x1.0" (8.4x2.8x2.5 cm)

Wt: 2.2oz. (62g)

Congresso Leon Mine, San Pedro Corralitos, Chihuahua, Mexico

A limonite matrix is host to hundreds of rounded nodules of honey-colored mimetite. These nodules range in size from miniscule to 0.2" (0.5cm) in diameter.When examined with a loupe, the mimetite appears very sparkly, and quite aesthetic.

Dims:4.3x2.7x1.8" (10.9x6.9x4.6 cm)

Wt: 9.5oz. (269g)

Congresso Leon Mine, San Pedro Corralitos, Chihuahua, Mexico

The top of this specimen is covered with hundreds of crystals and nodules of mimetite. The very tiny pieces of mimetite are crystalline, while the larger pieces are nodules, yellowish, and a little over 0.1" (0.3cm) in diameter. The matrix is a limonite/goethite mix, with minor crystalline calcite. There is no damage to this specimen.

Dims:1.7x1.5x1.1" (4.3x3.8x2.8 cm)

Wt: 1.6oz. (45g)

Congresso Leon Mine, San Pedro Corralitos, Chihuahua, Mexico

At least two dozen yellowish nodules of mimetite rest on a matrix with small rhombohedral calcite crystals. The mimetite contrasts nicely with the darker matrix. There is only minor damage at the edges of this specimen.

Dims:2.2x2.1x1.0" (5.6x5.3x2.5 cm)

Wt: 1.8oz. (52g)

Mt Bonnie Mine, Grove Hill, NT, Australia

The limonite/goethite matrix of this specimen is host to dozens of radiating, prismatic crystals of mimetite ranging in size from tiny to 0.3" (0.8cm) in length. One of the larger crystals is clearly double terminated. The display face of this specimen shows minor damage-only one crystal is noticeably damaged.