THE MINERAL HOPEITE

Dims: 1.6" x 1.3" x 0.7" (4.1 x 3.3 x 1.8 cm)

Wt: 20.1 g

#2 open pit, Broken Hill Mine, Kabwe, Zambia

Though showing a rather dull, red-brown coloration and only a rather low, pearly luster in a few places, this Hopeite specimen is nonetheless rather intriguing. The crystals that are not badly weathered occur in the form of orthorombic prisms that have asymmetrical six-sided cross-sections and shallow wedge-like domed terminations. The crystals are in excellent condition, as the only damage that they show is through natural wear, and they do not exceed 2 mm in length. Their color resembles that of limonite, though it varies quite a bit with respect to depth of color. The crystals are translucent to opaque and have a luster that ranges from pearly to dull, depending on the amount of wear that they have undergone. Some of the crystals appear to have been coated over with a similarly-colored material- I don't know if it is more Hopeite or a different mineral. The crust that the crystals forms coats most of what appear to be a few separate fragments of an igneous host rock that are held together by the Hopeite itself.

Dims: 2.0" x 1.8" x 0.6" (5.1 x 4.6 x 1.5 cm)

Wt: 28.0 g

#2 open pit, Broken Hill Mine, Kabwe, Zambia

This specimen possesses the largest Hopeite crystals that I have yet seen in my travels. The specimen consists of a flat, rusty-brown base of an unknown mineral that has a distincly botryoidal shape. On one edge of this host rock rest at least 15 Hopeite crystals which appear to be in excellent condition; only one that I can see is damaged and incomplete. They are in a complex orthorombic prismatic form and appear to have a lopsided hexagonal cross-section. They have a pale, rusty-red coloration and a dull, pearly-to-waxy luster, and are dimly to moderately translucent. The largest of these crystals measures about 0.4" (1.0 cm) in length and about half that in its other dimensions. It is attached to a small, flat acrylic base with a silicon-based soft glue.

Dims: 1.8 x 1.3 x 1.0" (4.6 x 3.3 x 2.5 cm)

Wt: 22.7 g

#2 open pit, Broken Hill Mine, Kabwe, Zambia

Scores of tiny Hopeite crystals rest on the dull brown host rock of this thumbnail specimen. These crystals do not exceed 0.1" (3 mm) in any dimension, and are in fair condition- most are heavily weathered. This also affects their orthorhombic prismatic form, as the weathered crystals appear to be very warped and incomplete. Only a few show very good form, with well-defined edges and clean faces that possess a bright pearly-to-vitreous luster. All have a rusty-brown coloration that may be due to iron absorbed from the host rock. The better-formed crystals are dimly translucent, but those that are weathered are opaque. There are thin crusts of material between the Hopeite clusters and the base rock- I do not know what they are made of, but some of them have a reniform habit.

Dims: 1.2 x 0.8 x 0.4" (3.0 x 2.0 x 1.0 cm)

Wt: 16.3 g w/ specimen box

#2 open pit, Broken Hill Mine, Kabwe, Zambia

This thumbnail specimen consists of a crust of tiny Hopeite crystals that rest on what appears to be an agate base. They do not exceed 0.1" (3 mm) in length and are in good condition, though one or two areas show definite damage. All have good orthorhombic prismatic form, a rusty-red color and a pearly luster, and are dimly transparent at best. The piece is affixed inside a plastic specimen box.