Szenicsite

Chemical formula: Cu<sup>2+</sup><sub>3</sub>Mo<sup>6+</sup>O<sub>4</sub>(OH)<sub>4</sub>

Szenicsite is a rare copper hydroxymolybdate, forming radial aggregates of intensely green, acicular crystals.

## Characteristics Szenicsite is a rare mineral from the molybdate group, chemically a hydrated copper molybdate. It is distinguished by its exceptionally attractive, intense, emerald-green color. It most often forms radial or fan-shaped aggregates composed of thin, acicular or bladed crystals, which can reach up to 2 cm in length. These specimens usually grow on host rocks, forming striking, bristly clusters. ## Physical Properties Szenicsite crystals are brittle and have a hardness of about 3-4 on the Mohs scale. They exhibit a vitreous luster, and an almost pearly luster on fracture surfaces. They are transparent to translucent. The mineral's density is approximately 4.25 g/cm³. ## Colors and Varieties This mineral occurs in one characteristic color: a vivid, emerald to grass-green. No color or commercial varieties are distinguished. ## History and Name Szenicsite was discovered in 1993 in the Jardinera No. 1 copper and molybdenum mine in the Atacama Desert, Chile. Its name honors Terry and Marissa Szenics, American mineral collectors and prospectors who found the first specimens of this mineral. It was described and approved as a new mineral species by the IMA in 1994 (IMA1993-033). ## Uses Szenicsite has no industrial applications. However, it is a highly valued and sought-after collector's stone due to its rarity, intense color, and attractive forms of occurrence.

Properties

Mohs hardness
3-4
Luster
Vitreous
Streak
Green
Density
4.25
Cleavage
Perfect on {010}
Fracture
Uneven
Transparency
Transparent to translucent
Crystal system
Orthorhombic

Diagnostic features

## Identification Szenicsite is relatively easy to identify visually for the trained eye. Its most characteristic features are its intense emerald-green color, vitreous luster, and typical radial aggregates of thin, acicular or bladed crystals. A green streak is also a helpful feature. ## Distinguishing from Similar Minerals Szenicsite is sometimes confused with other green secondary copper minerals, such as brochantite, antlerite, or malachite. It is distinguished from brochantite and antlerite by its brighter, more "electric" shade of green and often longer, more defined crystals. Malachite rarely forms such thin and sharp needles, and its aggregates are usually more massive, botryoidal, or fibrous. However, the key is the place of origin – almost all szenicsite specimens come from a single location in the world. ## Crystal Forms Crystals are elongated in the form of thin needles or flattened blades, often with oblique terminations. They almost always occur in radial, stellate, or fan-shaped aggregates, radiating from a single point.

Geological environment

## Genesis Szenicsite is a secondary mineral that forms in the oxidation zone (gossan) of copper and molybdenum deposits. It forms in desert conditions, as a result of the weathering of primary sulfides, such as chalcopyrite and molybdenite. It forms directly on the host rock, often in fractures and vugs. ## Mineral Associations This mineral co-occurs with other minerals of the oxidation zone. It is most commonly associated with powellite (often forming pseudomorphs after molybdenite), chalcopyrite, molybdenite, brochantite, lindgrenite, barite, and clay minerals. ## Localities The only confirmed and commercially significant occurrence of szenicsite in the world is its type locality – the Jardinera No. 1 mine, in the Inca de Oro district, Chañaral Province, Atacama Desert, Chile. It is an endemic mineral to this single deposit.

Rarity

Very rare

For collectors

## Quality Criteria The most highly prized szenicsite specimens are those that form large, sprawling, radial aggregates several centimeters in diameter. Key factors are: the intensity and saturation of the emerald-green color, the absence of damage to delicate needles, and good contrast with the light host rock. Specimens with crystals longer than 1-2 cm are considered exceptional. The luster and transparency of the crystals also significantly increase their value. ## Market Prices Szenicsite prices are high due to its rarity and origin from a single locality. Small, millimeter-sized aggregates can cost from tens to hundreds of dollars. Good quality miniatures (3-5 cm) with aesthetic aggregates fetch prices from several hundred to over a thousand dollars. Exceptional cabinet specimens, large and undamaged, can be valued at several thousand dollars or more. ## Popular Localities The only source of collector specimens is the Jardinera No. 1 mine in Chile. This mineral is not known from any other locality in the world, making it one of the most desirable "endemic" minerals.

Care and storage

## Cleaning Szenicsite specimens are very delicate and brittle. They should only be cleaned mechanically, using a soft brush to remove dust. Compressed air can be used from a safe distance. The use of water, and especially ultrasonics, is absolutely inadvisable and can destroy the specimen. ## What to Avoid Avoid contact with all chemicals, acids, and detergents. The mineral is sensitive to temperature changes and mechanical shocks. Due to its brittleness, even a slight impact can cause delicate needles to break off. Do not expose it to prolonged intense sunlight. ## Storage Szenicsite requires storage under stable conditions. It is best kept in a closed "micromount" box or a display cabinet, away from dust, moisture, and sources of vibration. Avoid placing other minerals directly on the fragile crystals.

External references

Sources

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