Cassiterite
Cassiterite is an oxide mineral prized by collectors for its exceptional color range, with several world-class Chinese localities.
About Cassiterite
Cassiterite is an oxide mineral in the rutile group and has the chemical formula SnO2. It crystallizes in the tetragonal system and is one of the most visually varied minerals in the collector market. Its combination of structural character and global distribution make it a recognized species in both systematic and aesthetic collections.
Identification & care
Cassiterite typically forms dipyramidal ('elbow twins'), prismatic, acicular; massive, granular, rounded alluvial pebbles ('stream tin'). Its color range is broad, including black, brown, yellow, red, white, and colorless. The luster is adamantine, greasy, sub-metallic, the streak is brownish white, white, greyish, and specimens are typically transparent, translucent, opaque. The cleavage is imperfect/fair on {100}; indistinct on {110}. The fracture is irregular/uneven, sub-conchoidal, which aids identification.
Collector context
How it forms
Cassiterite forms in granite pegmatites and greisens; hydrothermal tin veins; alluvial 'stream tin' placer deposits from erosion of primary sources. It is commonly found in association with wolframite, tourmaline, columbite-tantalite, topaz, mica, quartz, arsenopyrite.
Classic Chinese localities
**Dachang ore field**, **Yaogangxian W-Sn ore field**, and **Huanggang Fe-Sn deposit** are each a benchmark source for cassiterite. **Xianghualing Sn-polymetallic ore field** and **Xianghuapu Mine** are an important Chinese source for the species.
Why collectors care
Cassiterite is a frequently-sought species in serious collections because its habit is recognizable, its color often strong, and its best examples unmistakable even at a distance. Chinese material has driven much of the recent visual shift in the species — sharper crystals, deeper colors, cleaner matrix.
What affects value
Value in Cassiterite is assessed, in typical order of weight, against: (1) locality provenance; (2) size relative to the species norm; (3) crystal form and termination sharpness; (4) color saturation and zoning; (5) transparency and internal clarity; (6) matrix quality and aesthetic balance; (7) condition (absence of damage, chips, or repair). Cleaning quality and verified locality documentation act as multipliers across the above.
Naming history
The name Cassiterite has a specific etymological and historical context — see Mindat's reference entry for provenance details. We have retained naming data at the record level; published prose is paraphrased from factual fields rather than copied from source.
Available Cassiterite specimens
Cassiterite on Muscovite Mica, Xuebaoding, Sichuan, China
Cassiterite and Quartz Cluster, Yaogangxian Mine, China
Cassiterite and Calcite Cluster, Yaogangxian Mine, China
Cassiterite with Mica, Xuebaoding, Sichuan
Cassiterite with Quartz – Yaogangxian Mine, Hunan, China
Cassiterite Quartz Cluster – Purple Fluorite – Yaogangxian Mine
Cassiterite Cluster – Mica and Aquamarine – Xuebaoding, Sichuan
Cassiterite Crystal – Prismatic Form – Yaogangxian Mine, Hunan
Cassiterite Crystal – Columnar Striations – Yaogangxian Mine, Hunan
Cassiterite Crystals on Barite – Yaogangxian Mine, Hunan, China
Cassiterite Crystal – Octahedral Form – Xuebaoding Mt., Sichuan
Cassiterite Crystal, Xuebaoding, China
