Antimony

Chemical formula: Sb

Native antimony is a chemical element and a semimetal that naturally forms granular, scaly, or massive aggregates with a tin-white color and metallic luster.

## Characteristics Native antimony, the pure form of the element Sb, is a semimetal that crystallizes in the trigonal system. It most commonly occurs as granular, lamellar, scaly, or reniform aggregates. It rarely forms visible, pseudocubic or tabular crystals, usually of small size. Its characteristic tin-white to silvery-white color quickly tarnishes in air, becoming covered with a yellowish or iridescent oxide film. It is brittle and has perfect cleavage. ## Physical Properties Native antimony has a hardness of 3-3.5 on the Mohs scale, meaning it is relatively soft and can be scratched by a copper coin. Its density is significant, approximately 6.6-6.7 g/cm³. The luster is strongly metallic on fresh surfaces but quickly becomes dull. It is opaque. It exhibits perfect cleavage in one direction. ## Colors and Varieties The typical color of native antimony is tin-white or silvery-white. On weathered surfaces, a yellowish or blackening patina often appears, and sometimes an iridescent tarnish. No distinct color or commercial varieties are recognized, although it is sometimes confused with native arsenic, which often accompanies it in aggregates (forming the variety allemontite). ## History and Name The name antimony comes from the Latin word *antimonium*, used in the Middle Ages to refer to antimony sulfide (stibnite). The ultimate origin of the word is unclear but may derive from the Greek words *anti* (against) and *monos* (solitude), suggesting that this element does not occur alone. Antimony as an element was known in antiquity, and its pure form was scientifically described in the 18th century. ## Applications Native antimony is a minor source of metallic antimony, which has numerous industrial applications. It is mainly used in alloys with lead and tin for the production of batteries, ammunition, cable sheathing, and as a component of type metal and solders. Antimony compounds are used as flame retardants in plastics and textiles. For collectors, native antimony is significant as a native element mineral.

Properties

Mohs hardness: 3-3.5
Luster: Metallic
Streak: Gray
Density: 6.61-6.72
Cleavage: Perfect on {0001}
Fracture: Uneven
Transparency: Opaque
Crystal system: Trigonal

Diagnostic features

## Identification Native antimony is most easily identified by its tin-white color, strong metallic luster on a fresh fracture, high density, and perfect cleavage in one direction, which causes it to break into flat fragments. It is relatively soft and very brittle. A dull, yellowish, or iridescent patina is often visible on its surfaces. ## Distinguishing from Similar Minerals Native antimony is sometimes confused with native arsenic, with which it often co-occurs. Arsenic has a similar color but usually forms more reniform or botryoidal aggregates and has less distinct cleavage. It is distinguished from native bismuth by its silvery-white hue (bismuth has a pinkish hue) and the absence of the iridescent tarnish typical of bismuth. It is distinguished from galena by its lower hardness and lack of cubic cleavage. ## Crystal Forms Well-formed crystals are rare and usually appear as thick tabular or rhombohedral forms, often deformed and small. It is most commonly found in massive, granular, scaly, or radial aggregates. It also occurs as dendrites and reniform aggregates.

Geological environment

## Genesis Native antimony forms under hydrothermal conditions, in ore veins of low to medium formation temperature. It typically crystallizes in environments rich in silver, antimony, and arsenic, with low sulfur activity. It occurs in paragenesis with silver, lead, and zinc minerals. ## Mineral Associations It most commonly co-occurs with stibnite, native arsenic, allemontite (a mixture of antimony and arsenic), sphalerite, galena, pyrite, quartz, calcite, and various silver sulfosalts (e.g., dyscrasite, pyrargyrite). ## Localities Significant historical and collector localities include the Sala silver mine (Västmanland, Sweden), St Andreasberg in the Harz Mountains (Germany), and Příbram (Czech Republic). Beautiful specimens also come from the Consols mine in Broken Hill (New South Wales, Australia). Other known occurrences include Isère in France, Arezzo in Tuscany (Italy), and South Ham in Quebec (Canada).

Rarity

Not very common

For collectors

## Quality Criteria The most prized by collectors are specimens with well-formed, sharp crystals, which are very rare. Rich, massive aggregates with a pure, silvery-white color and strong metallic luster, without signs of oxidation, are also highly valued. Contrasts with associated minerals, such as white calcite or quartz, add to their attractiveness. Specimens from classic, historical localities, such as Sala or St Andreasberg, command higher prices. ## Popular Localities For collectors, specimens from historical European localities such as Sala in Sweden and St Andreasberg in Germany, which have yielded the best-known crystals, are most desirable. Specimens from the Consols mine in Broken Hill, Australia, are also classics. Massive, rich aggregates also come from localities in Canada (Quebec).

Care and storage

## Cleaning Native antimony specimens should only be cleaned mechanically, using a soft brush or paintbrush to remove dust and loose debris. Compressed air can be used. Avoid water and any chemical agents, as it reacts easily and tarnishes. ## What to Avoid Antimony is very sensitive to moisture and oxidation. Contact with water, acids, and other chemicals must be strictly avoided. It should not be heated or exposed to prolonged periods of humid air, which causes tarnishing and the formation of films. It is very brittle, so it should be protected from impacts and drops. ## Storage It is recommended to store specimens in dry, airtight containers, preferably with a desiccant (e.g., silica gel). Display should be in enclosed showcases, away from sources of moisture and sudden temperature changes. To preserve its metallic luster, contact with air should be minimized.