Chloroxiphite

Chemical formula: Pb²⁺₃Cu²⁺O₂Cl₂(OH)₂

Chloroxiphite is a rare, olive-green mineral from the halide group, distinguished by its resinous or adamantine luster and high density.

## Characteristics Chloroxiphite is a rare, secondary lead and copper mineral. It forms elongated, bladed crystals, often with striated surfaces, which can occur as radial or tangled aggregates. Its most characteristic visual feature is its dull, olive-green color and intense luster, which can be resinous or even adamantine on fresh surfaces. ## Physical Properties This mineral is relatively soft, with a hardness of 2.5 on the Mohs scale, meaning it can be scratched with a fingernail. It is exceptionally dense – its specific gravity is 6.76 g/cm³, which is noticeable even in small specimens. The crystals are transparent and exhibit perfect cleavage in one plane. ## Colors and Varieties Chloroxiphite typically occurs in shades of dull olive green. Its streak is a lighter, pale greenish-yellow color. No named color varieties or commercial varieties are distinguished. ## History and Name The mineral's name, given in 1923 by H.E. Buckley and G.T. Prior, comes from the Greek words *chloros* (green) and *xiphos* (sword or blade), referring to its typical color and bladed crystal form. It was discovered in the Higher Pitts mine in the Mendip Hills region (Somerset, England) and described based on material collected by Arthur Russell. ## Uses Due to its extreme rarity, chloroxiphite has no industrial applications. It is solely an object of interest for collectors and scientists.

Properties

Mohs hardness: 2.5
Luster: Resinous to Adamantine
Streak: Light green yellow
Density: 6.76
Cleavage: On <mi>{_101}</mi> perfect; {100} distinct.
Transparency: Transparent
Crystal system: Monoclinic

Diagnostic features

## Identification Chloroxiphite can be identified by its characteristic olive-green color, resinous to adamantine luster, and very high density. Its bladed, often striated crystals and softness (2.5 on the Mohs scale) are also key features. A pale greenish-yellow streak aids in identification. ## Distinguishing from Similar Minerals It can be confused with other secondary copper and lead minerals, such as boleite, diaboleite, or paralaurionite, which often co-occur with it. Chloroxiphite differs from them by its specific olive hue, crystal form, and combination of physical properties (luster, density). Accurate identification often requires chemical analysis. ## Crystal Forms Crystals are monoclinic, with an elongated, bladed or lanceolate shape. They often exhibit striations on their faces. They typically form radial, stellate, or haphazardly tangled aggregates embedded in the host rock.

Geological environment

## Genesis Chloroxiphite is a secondary mineral, forming in the oxidation zones of lead deposits, in environments rich in chloride ions. It forms as a result of groundwater reactions with primary lead sulfides (galena) in the presence of copper, often in voids within manganese ores. ## Mineral Associations It most commonly co-occurs with other rare, secondary minerals such as mendipite, diaboleite, cerussite, hydrocerussite, boleite, paralaurionite, and calcite. These minerals together form characteristic parageneses at the occurrence site. ## Localities The most important and classic locality for chloroxiphite, from which the best specimens originate, are the historic mines in the Mendip Hills region in Somerset, England (e.g., Higher Pitts Mine, Merehead Quarry). It is also known from small occurrences in Laurion, Greece, and several localities in the United States (Arizona).

Rarity

Very rare

For collectors

## Quality Criteria The most prized chloroxiphite specimens are characterized by well-formed, sharp crystals with an intense, adamantine luster. Rich radial aggregates or aesthetically arranged groups of crystals on a contrasting matrix are highly valued. Crystal size is crucial – specimens with blades exceeding a centimeter in length are exceptionally rare and sought after. ## Popular Localities By far the most desired specimens by collectors come from the historic type locality – the Mendip Hills region in England. Material from this location is considered the global standard for this mineral.

Care and storage

## Cleaning Specimens should be cleaned very carefully, using only a soft brush to remove dust. Due to its softness and perfect cleavage, ultrasonic cleaners and hard brushes should be avoided. Contact with water, especially demineralized water, should be minimal and brief. ## What to Avoid Chloroxiphite is sensitive to chemicals, especially acids, which can damage it. Sudden temperature changes and prolonged exposure to strong sunlight, which can cause fading, should be avoided. The mineral is very brittle and soft, so it should be protected from impacts and scratches. ## Storage It is recommended to store specimens in separate, padded boxes to avoid contact with harder minerals. It is best kept in stable conditions, away from heat sources and direct light.