PLATTNERITE
Specimen plt-2

Dims: 2-1/2" x 1-7/8" x 7/8"

Wt: 1.18 oz

Ojuela Mine, Mapimi, Durango, Mexico

Many tiny clusters of this strange lead oxide mineral reside on the limonite matrix of this specimen. Each Plattnerite cluster is made up of even tinier needlelike crystals that radiate from their respective central points. The clusters have a gray-black color and a very shiny vitreous to adamantine luster. Their shine makes for an excellent contrast against the dull, brown-black backdrop of limonite.

Dims: 2.7 x 1.3 x 1.2" (6.9 x 3.3 x 3.0 cm)

Wt: 2.1 oz. (59.8 g)

Ojuela Mine, Mapimi, Durango, Mexico

Dozens of crystalline and reniform Plattnerite formations rest on the goethite/limonite host rock of this specimen. These formations are tiny, not exceeding 0.1" (3 mm) in any dimension, but they are in excellent condition, as they show only a small amount of damage. The Plattnerite crystals are extremely small- they do not seem to exceed 1 mm in diameter. Thus, it is difficult to study their form without rather powerful magnification. They appear to have a moderately dark gray color and a bright adamantine luster, but I think that most of the luster is caused by tiny adamite crystals that rest on the Plattnerite. Actually, the Plattnerite crystals themselves rest on a druse of larger adamite crystals that have the standard pale yellow-green colo

Dims: 2.6 x 1.4 x 1.0" (6.6 x 3.6 x 2.5 cm)

Wt: 1.7 oz. (47.5 g)

Ojuela Mine, Mapimi, Durango, Mexico

This large thumbnail specimen is coated with a crust made up of at least 2 minerals, one of which is crystalline Plattnerite. The Plattnerite occurs in the form of tiny, radiating needles that do not exceed 0.1" (3 mm). Due to their small size and the fact that they are protected by the other mineral or minerals in the crust, they are in excellent condition. Their tetragonal form is rather difficult to study without magnification due to their size, but the crystals do have a dark gray-black coloration and a dull metallic luster. They are often obscured by the other minerals in the crust, which are made up of both hemimorphite and calcite. The hemimorphite tends to be in closer proximity to the Plattnerite, and as the crust spreads to the "reverse" of the specimen, the concentration of calcite increases. The base is made up of goethite and limonite.

Dims: 3.3 x 2.2 x 1.2" (8.4 5.6 x 3.0 cm)

Wt: 2.95 oz. (83.8 g)

Ojuela Mine, Mapimi, Durango, Mexico

Hundreds or even thousands of tiny Plattnerite needles coat a druse of white quartz crystals on this specimen. The Plattnerites do not exceed 0.1" (3 mm) in length, and are considerably thinner than 1 mm. There appears to be damage on the more exposed surfaces of the piece, but I canont tell whether they are human-induced or not. They are far too small for me to effectively study with a 10-power loupe, but appear to have reasonably good form. Their bright lusters are combined to create a subtle but noticeable sparkle in moderate light. All have the standard black color and are essentially opaque, though a few seemed to be at least translucent under bright light when viewed through the loupe. The quartz druse on which they rest is made up of small, well-formed crystals that are in good condition and have excellent form. They tend to be coated with a thin layer of either limonite or rust (not much difference!) and are translucent to dimly transparent. This druse rests on the base, which is made of limonite.

Dims: 3.1 x 1.6 x 0.7" (7.9 x 4.1 x 1.8 cm)

Wt: 1.69 oz. (48.0 g)

Mapimi, Durango, Mexico

A druse made up of hundreds of tiny, intergrown Plattnerite crystals coats the limonite host rock of this specimen. These crystals are tiny- most do not exceed 1 mm in diameter- but appear to be in excellent condition and have good tetragonal form. Their black color and bright, adamantine luster are standard for their species. The druse covers almost the entire limonite base and is itself partly covered by a druse of warped and heavily-intergrown calcite blades.

Dims: 1.1 x 1.1 x 0.9" (2.9 x 2.8 x 2.3 cm)

Wt: 0.7 oz. (18 g) w/ specimen box

Mina Ojuela, Mapimi, Durango, Mexico

This thumbnail piece consists of a crust of massive Plattnerite that covers a limonite/hematite base. Most of the Plattnerite crust is covered by a thin layer of crystalline calcite, giving the illusion of crystal form to the lead oxide mineral. The Plattnerite has a dark gray-black color and a submetallic luster. The piece is affixed inside a plastic thumbnail box with a removable putty.

Dims: 1.1 x 1.0 x 0.6" (2.9 x 2.6 x 1.6 cm)

Wt: 0.6 oz. (17 g) w/ specimen box

Mina Ojuela, Mapimi, Durango, Mexico

A crust of apparently massive Plattnerite covers the limonite base of this thumbnail piece. Upon examination with a loupe, however, one can see many tiny, black spiky crystals. These crystals may be calcites, but are too small to effectively study even under 10x magnification. The Plattnerite has a black color and a lovely sparkle caused by the tiny crystals. A few larger, brown calcite blades grow off of one edge of the crust. These are in very good condition and show good form, a pearly luster, and moderate transparence. The piece is affixed inside its thumbnail box with a removable putty.

Dims: 1.1 x 0.7 x 0.7" (2.9 x 1.8 x 1.8 cm)

Wt: 0.5 oz. (15 g) w/ specimen box

Mina Ojuela, Mapimi, Durango, Mexico

The limonite base of this thumbnail specimen is partly covered with a massive Plattnerite crust. This crust shows no evidence of inherent crystal form and has a gray color and submetallic luster where exposed. It is mostly covered by a druse of tiny calcite crystals which have a brown-black color and show good trigonal form- one small cluster is large enough to be seen without magnification. A few nodules of reniform limonite/hematite are also visible on the crust. The piece is affixed inside its thumbnail box with a removable putty.

Dims: 1.8 x 1.5 x 1.0" (4.6 x 3.8 x 2.6 cm)

Wt: 1.2 oz. (33 g)

Granite Gap, Hidalgo County, New Mexico, U.S.A.

A druse of microscopic Plattnerite needles rests on the pale brown base rock of this hand specimen. The needles are in excellent condition and measure considerably less than 1 mm in length. All likely have excellent tetragonal form, though one would need a microscope to study it. All are likewise black and have the adamantine luster that is standard for this mineral. The druse is partly covered by a druse of clear calcites.