Shinichengite
Chemical formula: Ca<sub>5</sub>[BSi<sub>2</sub>O<sub>7</sub>(OH)<sub>2</sub>]<sub>2</sub>·6H<sub>2</sub>O
Shinichengite is a very rare, colorless or white hydrated calcium borosilicate, forming small, tabular crystals.
Properties
- Mohs hardness
- 3
- Luster
- Vitreous
- Streak
- White
- Density
- 2.55
- Cleavage
- Perfect on {0001}
- Fracture
- Uneven
- Transparency
- Transparent to Translucent
- Crystal system
- Trigonal
Diagnostic features
## Identification Identification of shinichengite is practically impossible without advanced analytical methods, such as X-ray diffraction (XRD) or spectroscopy. Under collecting conditions, identification relies on a label from a reliable source and knowledge of associated minerals from the type locality. ## Distinguishing from Similar Minerals It can be confused with other white or colorless secondary minerals found in borate deposits, such as calcite, gypsum, or other rare borosilicates. Visual differentiation is unfeasible; laboratory confirmation is required. ## Crystal Forms Shinichengite forms thin, tabular crystals with a hexagonal outline, often grouped into rosettes, fan-shaped, or spherical aggregates. The crystals are very small, usually less than half a millimeter in size.
Geological environment
## Genesis Shinichengite is a hydrothermal mineral. It forms in the late stages of mineralization in borate skarns, which developed at the contact of dioritic intrusions with Proterozoic, magnesium-rich marbles. ## Mineral Associations This mineral coexists with other borate and silicate minerals. At the type locality, it was found in association with szaibelyite, kusachiite, olshanskyite, wightmanite, fluoborite, hydroxylborite, calcite, and serpentine. ## Localities The only confirmed occurrence of shinichengite in the world is its type locality: the Shinicheng boron deposit, in Kuandian County, Liaoning Province, northeastern China.
Rarity
Extremely rare
For collectors
## Quality Criteria As a "micromount" mineral, its value is primarily determined by the richness and quality of the crystals on the rock matrix, rather than their individual size. The most desirable specimens are those with well-formed, sharp crystals forming aesthetic aggregates, clearly contrasting with the matrix rock. The presence of rare associated minerals is also crucial. ## Popular Localities The only source of specimens is the Shinicheng mine in China. Material from this locality is extremely difficult to obtain and appears on the collector's market sporadically.
Care and storage
## Cleaning Due to its extreme rarity and delicacy, shinichengite specimens should only be cleaned if absolutely necessary, using compressed air to remove dust. Contact with water and any chemicals should be avoided. ## What to Avoid Avoid ultrasonic cleaners, chemical agents, acids, and high temperatures. The mineral is soft and easily susceptible to mechanical damage. As a hydrated mineral, it may be sensitive to changes in humidity and temperature, which can lead to dehydration and destruction. ## Storage Specimens should be stored under stable conditions, in sealed "micromount" containers, protecting them from dust, humidity, direct sunlight, and shocks. It is best to store it within its matrix rock.