Abhurite
Chemical formula: Sn<sup>2+</sup><sub>21</sub>O<sub>6</sub>(OH)<sub>14</sub>Cl<sub>16</sub>
Abhurite is a very rare tin mineral, forming characteristic, hexagonal crystals as a result of the corrosion of metallic tin in saltwater.
Properties
- Mohs hardness
- 2
- Luster
- Adamantine to resinous
- Streak
- White
- Density
- 4.35
- Cleavage
- Perfect on {0001}
- Fracture
- Uneven
- Transparency
- Transparent to translucent
- Crystal system
- Trigonal
Diagnostic features
## Identification The most important diagnostic features of abhurite are its characteristic hexagonal crystal habit, pale yellow color, adamantine luster, extreme softness (Mohs hardness 2), and perfect cleavage. The context of its occurrence is also crucial – almost exclusively on corroding, metallic tin from shipwrecks. ## Distinguishing from Similar Minerals Abhurite is sometimes confused with pyromorphite or mimetite due to their similar hexagonal habit and yellowish color. However, it can be easily distinguished by its much lower hardness – both pyromorphite and mimetite are distinctly harder (3.5-4). Wulfenite, although sometimes tabular, is also harder and has a different chemical composition. ## Crystal Forms Abhurite crystals take the form of thin or thick hexagonal tablets. They often form fan-shaped or rosette aggregates, as well as dense crusts composed of small, overlapping scales.
Geological environment
## Genesis Abhurite is a secondary mineral, formed under very specific conditions. It forms as a result of the reaction of metallic tin with salty, chloride-rich seawater. It is therefore a product of tin corrosion in a submarine environment. Its formation is associated with human activity (shipwrecks), although the process itself is natural. ## Mineral Associations This mineral occurs directly on the surface of metallic tin, which it replaces. It is most often accompanied by other, simpler tin corrosion products, such as romarchite (SnO) and cassiterite (SnO₂). ## Localities The type locality is the wreck of the SS Carnatic in the Red Sea off the coast of Saudi Arabia. Abhurite has also been identified on tin ingots from other historical shipwrecks, including off the coast of Cornwall in the United Kingdom.
Rarity
Very rare
For collectors
## Quality Criteria The collector's appeal of abhurite specimens depends on several factors. Specimens with well-formed, sharp crystals of the largest possible diameter are most highly valued. The intensity and purity of the color, as well as the richness of the crust on the matrix (a fragment of a tin ingot), are also important. Aesthetic, rosette-like crystal aggregates are particularly sought after. ## Popular Localities The most known and valued specimens come from the type locality – the SS Carnatic wreck. Material from this location is considered classic for this species.
Care and storage
## Cleaning Abhurite is an extremely delicate and soft mineral. To remove dust, use only a soft brush or carefully blow it off with a stream of air from a safe distance. Absolutely avoid washing in water and using any chemical agents. ## What to Avoid Specimens should be protected from any physical contact, impacts, and friction, which can cause scratching or complete destruction of the crystals. The mineral is sensitive to acids and other chemicals. Avoid sudden changes in temperature and humidity. ## Storage Abhurite specimens are best stored in closed, padded "micromount" boxes, which protect them from mechanical damage, dust, and humidity changes. Do not expose it to direct sunlight.