Svabite
Chemical formula: Ca<sub>5</sub>(As<sup>5+</sup>O<sub>4</sub>)<sub>3</sub>F
A rare calcium arsenate of the apatite group, distinguished by hexagonal crystals and occurrence in skarn deposits.
Properties
- Mohs hardness
- 5
- Luster
- Vitreous to resinous
- Streak
- White
- Density
- 3.58-3.71
- Cleavage
- Indistinct on {0001}
- Fracture
- Conchoidal to uneven
- Transparency
- Transparent to translucent
- Crystal system
- Hexagonal
Diagnostic features
## Identification A key diagnostic feature is the hexagonal crystal habit, typical for minerals of the apatite group. A Mohs hardness of 5, relatively high density, and vitreous luster are also helpful in identification. Occurrence in manganese skarns in association with other rare minerals is a strong indicator. ## Distinguishing from Similar Minerals Svabite can be confused with other minerals of the apatite group. It differs from fluorapatite by its significantly higher density and occurrence environment. Mimetite, although also an arsenate, usually forms yellow or brown crystals and has an even higher density. Johnbaumite is visually indistinguishable and requires advanced chemical analysis for identification. It differs from visually similar quartz by its much lower hardness, and from calcite by its lack of reaction with hydrochloric acid and greater hardness. ## Crystal Forms It most commonly forms hexagonal, prismatic crystals, terminated by flat pinacoids or pyramids. It also occurs as granular aggregates, radial aggregates, or masses filling small rock fissures.
Geological environment
## Genesis Svabite is a mineral typical of metamorphosed skarn deposits, rich in manganese and iron, which formed at the contact of magmatic intrusions with carbonate rocks. It is also found in some hydrothermal ore veins. ## Mineral Associations It often co-occurs with other skarn minerals, such as calcite, hausmannite, manganite, hematite, as well as rarer arsenates like hedyphane, manganberzeliite, and tilasite. In the Franklin locality in the USA, it is associated with franklinite and willemite. ## Localities The most important and classic svabite localities are in Sweden, in the Harstigen (type locality), Jakobsberg mines, and the famous Långban complex. Significant specimens also come from the historic mining district of Franklin in New Jersey, USA.
Rarity
Rare
For collectors
## Quality Criteria The most prized by collectors are specimens with sharp, well-formed, lustrous, and transparent crystals. Specimens where svabite occurs on a contrasting rock matrix or in association with other rare, aesthetic minerals are also highly valued. Crystal size is an important factor, as large, undamaged prisms are exceptionally rare. ## Popular Localities The best specimens in the world are considered to come from two classic localities: Långban in Sweden and Franklin in New Jersey, USA. They provide the most aesthetic and best-formed crystals, often in interesting mineral associations.
Care and storage
## Cleaning Svabite specimens should be cleaned very carefully, using a soft brush and distilled water. Ultrasonic cleaners should be avoided, as they can cause fractures in brittle crystals. ## What to Avoid As an arsenate, the mineral is toxic – avoid inhaling dust and wash hands after each contact with the specimen. A hardness of 5 means it is susceptible to scratching by harder minerals, such as quartz. It should be protected from contact with acids and strong chemicals. It should not be exposed to prolonged sunlight or sudden temperature changes. ## Storage It is recommended to store svabite specimens in separate, padded boxes to protect them from scratching and mechanical damage. Display in enclosed showcases protects against dust and limits direct contact.