THE MINERAL ORPIMENT

Dims: 3.0" x 2.2" x 1.6"(7.6 x 5.6 x 4.1 cm)

Wt: 6.49 oz.184.1 g)

Shimen, Hunan Province, China

I have been told that Orpiment crystals are rather rare. This specimen consists of almost 20 long, prismatic Orpiment crystals that probably pseudomorphed from Realgar, as is usually the circumstance. They have a dull golden color, are translucent, and have a pearly luster. There is a substantial amount of damage to the crystals, and the specimen should be handled with care and kept in a cool, dark place, as they are delicate and light will speed up their decay. The crystals range in size from about 0.3 - 1.0"(0.8 - 2.5 cm) in length, erupting from a bed of white calcite. The calcite itself rests on a base that seems to be made up mostly of Orpiment, and there is one visible spot of bright red realgar.

Dims: 6.1" x 5.5" x 3.7"(15.5 x 14.0 x 9.4 cm)

Wt: 4 lbs., 9.3 oz.(2.077 kg)

Nevada, U.S.A.

This large hand specimen consists almost entirely of semicrystalline Orpiment. It has the standard yellow-golden-orange coloration and the dull pearly luster that one expects of this material, and is only dimly translucent at best. Though it does show definite crystalline tendencies, there are no complete crystals visible. However, there are some tiny bits of partly-decayed realgar still visible on the specimen, which makes me think that the Orpiment did NOT start out as realgar- I believe that it originally formed as Orpiment. A few scraps of a black host rock are attached, but these do not make up a substantial percentage of the specimen's mass.

Dims: 4.6" x 2.5" x 1.5" (11.7 x 6.4 x 3.8 cm)

Wt: 12.7 oz. (360 g)

Shimen Mine, Shimen, Hunan Province, China

This Orpiment specimen consists of a cluster of long monoclinic prismatic crystals. Though there is much visible damage on some of their termiations, their size is exceptional- many of these crystals exceed 4" (10 cm) in length! All have a warped but definable crystal form and a bright, pearly-to-vitreous luster that shows an almost metallic shine in a few areas. Their color is a dull gold that has a hint of orange and most are surprisingly transparent, though their clarity is often spoiled due to internal fracturing. There is a small amount of what I would think is white calcite attached to the cluster in a few places, but no host rock.

Dims: 4.0 x 3.8 x 2.4" (10.2 x 9.7 x 6.1 cm)

Wt: 12.5 oz. (354 g)

Quiruvilca, La Libertad Department, Peru

This hand specimen consists of several Orpiment crystals that rest on a pyrite-laden host rock. A few of the crystals are damaged, but most appear to be in good condition. I believe that none of them exceed 0.8" (2.0 cm) along their longest axis. It is difficult to gauge their size or study their crystal form, as all are covered with a 0.1" (3 mm)-thick crust that is made up of thousands of other, tiny Orpiment crystals (see the second image). Several very exposed areas of this crust are visibly damaged due to crushing, but otherwise it is in good condition. It has a dark yellow-orange coloration and an almost silky luster, whereas the larger crystals beneath it are brighter in color and have a pearly luster. The Orpiment rests on what appears to be a thin layer of white crystalline calcite sandwiched between it and the host rock. I think that this Orpiment specimen is one of the most interesting that I have ever seen.

Dims: 3.2 x 2.7 x 2.2" (8.1 x 6.9 x 5.6 cm)

Wt: 14.4 oz. (409 g)

Getchell Mine, Humboldt County, Nevada, U.S.A.

A substantial part of the mass of this hand specimen is made up of Orpiment, in the form of both crystals and masses. Those crystals that are present are mostly broken, but a few are intact and show reasonably good though warped monoclinic prismatic or bladed form. They possess a few well-defined edges and some clean faces that have a dull luster. Where damaged, the Orpiment has a brighter, pearly luster. All have a deep golden-yellow color and are dimly translucent. They are accompanied by several very small realgar crystals, most of which are damaged or broken. A substantial amount of calcite is also present, and possibly another metallic sulfide in a massive form.

Dims: 2.4 x 2.1 x 1.5" (6.2 x 5.3 x 3.9 cm)

Wt: 4.8 oz. (135 g)

Twin Creeks Mine, Humboldt County, Nevada, U.S.A.

Scores of Orpiment blades permeate the dull, black matrix rock of this hand specimen. Most of the visible crystals are broken or damaged, but many are intact, reaching lengths of nearly 0.3" (8 mm). The intact blades have an excellent monoclinic form that appears nearly pseudo-orthrombic, and show the standard golden-yellow color and a slightly dull, pearly luster. They are transparent, but their clarity is spoiled by a superthin coating of a black dust that actually forms part of the matrix rock. Many other crystals are partly or completely buried in this matrix along one edge of the piece.

Dims: 2.3 x 2.1 x 1.1" (5.9 x 5.2 x 2.8 cm)

Wt: 2.3 oz. (65 g)

Twin Creeks Mine, Humboldt County, Nevada, U.S.A.

Scores of tiny, intergrown Orpiment crystals coat the black base of this hand specimen. These crystals do not exceed 0.1" (3 mm) in length or diameter and are generally in good condition - those that are directly exposed tend to be broken, but many are protected and in excellent condition. Though heavily intergrown, they appear to have excellent monoclinic prismatic form. Their yellow color is visible, though not obvious, and all have a bright pearly luster and are transparent.

Dims:1.8x0.9x0.8" (4.6x2.3x2.0 cm)

Wt: 0.7oz. (20g)

Hunan prov., China

This specimen consists of a euhedral orpiment crystal growing alongside scalenohedral calcites. There are two calcite crystals present. They are 1.6" (4.1cm) and 0.8" (2.0cm) long, respectively. The orpiment crystal shows considerable damage on the back side where it was pried from the host rock. It appears that there was at one time a parallel growth crystal on the orpiment-a small amount of this crystal and its termination may still be seen. The larger calcite has a small amount of powdery yellow orpiment on one edge where another orpiment crystal was at one time.

Dims: 2.0x1.3x1.7" (5.1x3.3x4.3 cm)

Wt: 2.30 oz. (65 g)

Elbrusskiy Mine, North Caucasus, Russia

This is a very pretty orange-yellow orpiment specimen. While there are areas of the common foliated yellow orpiment, most of this specimen's orpiment is in a dozen radial clusters of translucent (almost transparent) orange-yellow crystals. The crystals are very sparkly, giving the specimen an almost gemmy appearance. The only damage to the crystals (along the edges where this specimen was separated from its neighbors) is apparent as the translucent orange-yellow crystals become yellow and nearly opaque when they are bent. This gives the sides of the radial clusters an interesting appearance, as they each appear to be edged with yellow radiating crystals - a nice contrast.

Dims: 1.5x1.5x0.9" (3.8x3.7x2.4 cm)

Wt: 1.7 oz. (47.5g)

Elbrusskiy Mine, North Caucasus, Russia

Typical of Elbrusskiiy orpiments, this specimen has translucent yellow-orange crystals in radial clusters. Under a loupe, the crystals almost look transparent. They have a lot of sparkle for orpiment, looking vitreous. The only damage is along the edges, where cleaving (or flexing) the crystals has turned them a golden yellow and opaque, although they still have that bright luster. This is a pretty specimen, even if the individual crystals are small.

Dims: 1.6x1.1x0.6" (4.2x2.7x1.5cm)

Wt: 0.82 oz. (23.2g)

Elbrusskiy Mine, North Caucasus, Russia

This yellow-orange orpiment specimen consists of a dozen or more radial clusters of the crystals resting upon the white host rock. Except on the edges of the specimen, the crystals of orpiment are nearly transparent and much more orange than is typical for orpiment. Flexing the crystals (as was done along the sides when the specimen was isolated) turns them into an opaque, bright yellow, foliated clusters with a pearly luster. The color contrast along the sides is very appealing. Orpiment specimens should be stored in the dark, as they will degrade after several years of exposure to light (less if it is bright sunshine).

Dims: 1.5x0.9x0.7" (3.8x2.4x1.9cm)

Wt: 0.78 oz. (22.2g)

Elbrusskiy Mine, North Caucasus, Russia

Like other Elbrusskiy orpiment specimens, this one has that unusual transparent orange color. The crystals are radial clusters of transparent orange, with excellent terminations. On one side (where this specimen was separated from its neighbor), the individual crystals hare turned the usual bright opaque yellow of orpiment, looking like crystalline gold leaf. The transparent orange crystals are flexible, but bending them turns them into that opaque yellow form (but there are a lot of crystals, and it is neat to watch).

Dims: 3.98x3.58x1.65" (10.1x9.1x4.2cm)

Wt: 13.87oz (392g)

Potosi District, Humboldt County, Nevada, USA

This large hand specimen is composed of orange and yellow crystals of orpiment, coating both sides of a plate of a black host rock. While the crystals are intergrown and incomplete, there are several large ones, including a book of flat crystals with a clean face. The color and luster of this specimen is quite good, although most of the exposed surfaces are fracture, and only a few crystals have natural terminations. The specimen has a crack that nearly penetrates it, and I suspect that some flexible crystals of orpiment are the glue that holds it together. Likewise, the nice large crystal (see the closeup image) is also somewhat loose, so care should be taken when handling this specimen.

Dims: 3.02x2.17x1.52" (7.66x5.50x3.86cm)

Wt: 7.24oz (205.0g)

Mecur Mine, Tooele County, Utah, USA

Thie hand specimen of orpiment has classic orpiment crystals in a vein of a white mineral filling a crevice in a black host rock. The orpiment crystals are translucent and orange, but the surfaces are generally yellow with a very high vitreous luster, a common response of orpiment to the strain of being fractured or flexed. Some thin sheets of the orpiment are rolled up into flexible coils, and most of the yellow material has been noticeably bent.