URANOCIRCITE
Specimen urc-5

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

Wt: 2.3 g

Virgem de Lapa area, Minas Gerais, Brazil

I personally wouldn't be able to tell this specimen apart from the nearest autunite, but I haven't seen many uranium minerals before working on this site. The crystals are, of course, bright yellow, tabular, and surprisingly opaque for their thinness. The piece seems to be made up almost entirely of the mineral, though there are some suspiciously botryoidal, black formations that remind me of goethite. The uranocircite crystals are quite small, measuring just over 1/16 inch in diameter. I love the colors of uranium minerals like this; the yellow simply looks too bright to be a natural occurrence!

Dims: 3.7 x 2.0 x 0.9" (9.4 x 5.1 x 2.3 cm)

Wt: 4.38 oz. (124.2 g)

Vogtland, Sachsen, Germany

This small hand specimen consists of a few flattened clusters of warped Uranocircite tablets. Every cluster shows some evidence of damage, but all tend to be rather flat, anyway, and likely formed in a narrow crevice. Their tetragonal form is all but undefinable, though some form is noticeable. All have the standard bright yellow coloration and pearly, micaceous luster of this mineral, and are opaque. The host rock on which they rest appears to be a very finely-grained granite.

Dims: 4.7 x 4.3 x 1.6" (11.9 x 10.9 x 4.1 cm)

Wt: 1 lb., 5.2 oz. (602 g)

Vogtland, Sachsen, Germany

Many flattened Uranocircite blades are intergrown in scattered clusters on the granitic host rock of this piece. Individual blades are difficult to discern, and none appear to be complete and integral, most likely because they formed in a narrow crevice. Their form, likewise, is definable, but not very good. All have the bright yellow coloration and near-opacity that are standard for this mineral, and show a pearly luster. I cannot be sure that the host rock is made of granite, but it is definitely metamorphic in nature.

Dims: 3.7 x 3.2 x 1.9" (9.4 x 8.1 x 4.8 cm)

Wt: 1 lb., 2.2 oz. (518 g)

Vogtland, Sachsen, Germany

This hand specimen consists of granular, possibly granitic base rock on which rest several flattened clusters of tabular Uranocircite crystals. These clusters appear to be in very good condition, as fresh damage is minimal. They are probably flattened because they formed in a narrow crevice between their base and another rock. The crystals are somewhat warped due to their intergrowth and the lack of space, but many have a surprisingly good tetragonal tabular form, with sharp edges and clean faces that possess a pearly luster. All have the standard bright-yellow coloration of Uranocircite, and a few of the more exposed blades are so thin that they are dimly transparent! There is a black discoloration on portions of the base rock, parts of which have a definitely dendritic shape.

Dims: 5.4 x 3.4 x 1.6" (13.7 x 8.6 x 4.1 cm)

Wt: 1 lb., 2.7 oz. (529 g)

Vogtland, Sachsen, Germany

Scores of tiny, flattened Uranocircite blades coat a portion of the granular host rock of this large hand specimen. The blades do not exceed 0.2" (5 mm) in diameter and are flattened and heavily intergrown, so it is very difficult to assess any damage. They have a crystalline form, but it is all but destroyed by their intense intergrowth and lack of growing space. They do have the bright yellow coloration and pearly luster that are standard for this mineral, however. The host rock appears to be metamorphic in origin- I would guess that it is a finely-grained granite from its appearance.

Dims: 3.5 x 2.9 x 1.2" (8.9 x 7.4 x 3.0 cm)

Wt: 7.69 oz. (218 g)

Vogtland, Sachsen, Germany

A loose cluster of many tiny Uranocircite blades rests on the granitic base of this hand specimen. These blades do not exceed 0.1" (3 mm) in diameter and are generally in good condition, though some damage is visible. All have good tetragonal tabular form and the standard bright yellow color and pearly luster. When placed under ultraviolet light, they glow a bright green.