Aplowite
Chemical formula: Co<sup>2+</sup>S<sup>6+</sup>O<sub>4</sub>·4H<sub>2</sub>O
Aplowite is a rare, hydrated cobalt sulfate, forming pink, encrusting or earthy aggregates, closely related to moorhouseite.
Properties
- Mohs hardness
- 3
- Luster
- Vitreous
- Streak
- Pale pink
- Density
- 2.56
- Cleavage
- Good on {010}
- Fracture
- Uneven
- Transparency
- Transparent to translucent
- Crystal system
- Monoclinic
Diagnostic features
## Identification Aplowite is identified by its characteristic pink color, occurrence as earthy or powdery encrustations on cobalt minerals, and its instability in dry air. Its reaction to humidity (easy hydration and dehydration) is a key diagnostic feature. ## Distinguishing from Similar Minerals Aplowite is visually almost identical to moorhouseite, which is its dehydration product. Distinguishing the two minerals without X-ray diffraction (XRD) analysis is practically impossible. It can also be confused with erythrite, which, however, usually forms better-developed, acicular or radial aggregates and has a more intense, carmine color. ## Crystal Forms Aplowite crystals are extremely rare and appear as microscopic, thin, hexagonal plates. It typically forms very fine-grained, powdery or earthy aggregates and encrustations.
Geological environment
## Genesis Aplowite is a secondary mineral, forming in the oxidation (weathering) zones of ore deposits containing cobalt, such as skutterudite or cobaltite. It forms under relatively low humidity conditions as a dehydration product of hexahydrate sulfate or the weathering of primary cobalt sulfides and arsenides. ## Mineral Associations It co-occurs with other secondary cobalt and nickel minerals, such as moorhouseite, bieberite, erythrite, annabergite, as well as with pyrite, sphalerite, galena, and skutterudite. ## Localities The most important occurrences of this rare mineral include its type locality at the Magnet mine in British Columbia (Canada). It has also been reported in mines in the Cobalt-Gowganda area in Ontario (Canada), in Bou Azzer (Morocco), and in mines near Jáchymov (Czech Republic) and Schneeberg (Germany).
Rarity
Very rare
For collectors
## Quality Criteria For collectors, the most valuable specimens are those with visible, even microscopic, aplowite crystals. Rich, intensely colored encrustations on a contrasting rock matrix or in association with other cobalt minerals, e.g., erythrite, are also prized. Due to its instability, proper specimen preservation is crucial. ## Popular Localities Specimens from the type locality in British Columbia and from historical sites in the Cobalt region of Ontario are most sought after by specialized collectors.
Care and storage
## Cleaning Due to its high fragility and water solubility, aplowite should not be cleaned with water. Only gentle dust removal with a soft brush or a stream of compressed air from a distance is permissible. ## What to Avoid Contact with water and other liquids that can dissolve it must be strictly avoided. The mineral is unstable in dry air – it easily loses water, transforming into moorhouseite. It should be protected from high temperatures and direct sunlight. ## Storage Aplowite requires storage in sealed, airtight containers (e.g., "membrane box" type or in vials) to maintain stable ambient humidity and prevent its dehydration. It should be stored in a dark and cool place.