Siidraite
Chemical formula: Pb²⁺₂Cu¹⁺(OH)₂I¹⁻₃
Siidraite is a rare lead-copper halide, forming small, tabular crystals with an intense red color and adamantine luster.
Properties
- Mohs hardness
- 2
- Color
- Yellow
- Luster
- Adamantine
- Streak
- Yellow
- Density
- 6.505
- Cleavage
- Perfect on {0001}
- Fracture
- Micaceous
- Transparency
- Translucent
- Crystal system
- Orthorhombic
Diagnostic features
## Identification Siidraite is recognizable by its unique occurrence environment (volcanic fumaroles), intense red color, adamantine luster, and characteristic form of small, tabular crystals. Due to its size, identification requires the use of a stereoscopic microscope. ## Distinguishing from Similar Minerals It can be confused with other rare, red minerals from the Tolbachik volcano fumaroles, such as ilinskite or avdoninite. Definitive differentiation requires advanced analytical methods, such as Raman spectroscopy or X-ray diffraction (XRD), due to visual similarity and co-occurrence. ## Crystal Forms Crystals are very small, usually below 0.2 mm. They take the form of thin, hexagonal tablets or elongated blades. They often form fan-shaped, rosette-like, or spherical aggregates.
Geological environment
## Genesis Siidraite is a mineral of volcanic origin. It forms through sublimation from volcanic gases in active fumarole zones, at temperatures of approximately 100-150°C. It crystallizes on the surfaces of volcanic rocks, such as basaltic lava crust. ## Mineral Associations This mineral co-occurs with other rare volcanic exhalation products. At the type locality (Tolbachik volcano), it was found in association with minerals such as iodargyrite, ilinskite, belloite, cotunnite, chalcanthite, and native sulfur. ## Localities The only confirmed occurrence of siidraite in the world is its type locality - the Yadovitaya fumarole on the second cone of the northern eruption of the Great Fissure Tolbachik, Tolbachik volcano, Kamchatka, Russia.
Rarity
Very rare
For collectors
## Quality Criteria The quality of siidraite specimens, which are exclusively microminerals, is assessed based on several criteria. The most important is the size and quality of crystal formation – the larger, sharper, and better-formed the tablets, the more valuable the specimen. Rich clusters and aggregates with an intense red color, contrasting with a light rock matrix, are desirable. Association with other rare minerals from this locality is also significant. ## Popular Localities The only source of siidraite specimens is its discovery site: Tolbachik volcano in Kamchatka. All samples available on the collector's market come from this single, specific locality.
Care and storage
## Cleaning Due to its extreme rarity, small size, and delicacy, siidraite specimens are practically not subject to cleaning. Any attempts at mechanical or chemical cleaning can irreversibly destroy the sample. They should be left undisturbed on their original rock matrix. ## What to Avoid Contact with any chemicals, including water, should be avoided. The crystals are very soft and brittle, susceptible to mechanical damage. They should be protected from high temperatures, direct sunlight, and changes in humidity. ## Storage Siidraite specimens should be stored exclusively in specialized, sealed "micromount" boxes, which protect them from dust, moisture, and physical damage. Display is possible only under a microscope.