Tourmaline
Tourmaline is a silicate mineral valued for its hardness and gem potential, with several world-class Chinese localities.
About Tourmaline
Tourmaline belongs to the silicate class in the tourmaline supergroup and has the chemical formula AD₃G₆(T₆O₁₈)(BO₃)₃X₃Z (complex borosilicate supergroup). It crystallizes in the trigonal system and ranks among the harder species, with lasting durability. Its combination of structural character and global distribution make it a recognized species in both systematic and aesthetic collections.
Identification & care
Crystals commonly develop as prismatic with triangular cross-section, striated lengthwise; massive. Its color varies widely across the species. The luster is vitreous, the streak is white, and specimens range from transparent to opaque. The fracture is conchoidal, which is one of its key identifying features.
Collector context
How it forms
The geological setting for Tourmaline is typically granitic pegmatites, metamorphic rocks, hydrothermal veins. It is commonly found in association with quartz, feldspar, lepidolite, beryl, apatite.
Classic Chinese localities
Documented Chinese occurrences are recorded at Shangbao Mine, Jiama Cu-polymetallic deposit and Xianghualing Sn-polymetallic ore field, among others.
Why collectors care
Tourmaline occupies a rare position: it matters equally to specimen collectors and to the gem trade. Crisp natural crystals with saturated color and good clarity command premium pricing and are among the highest-prestige targets in any systematic collection.
What affects value
Value in Tourmaline is assessed, in typical order of weight, against: (1) locality provenance; (2) crystal size; (3) transparency and internal clarity; (4) color intensity and saturation; (5) crystal form and termination sharpness; (6) matrix and associated-species aesthetics; (7) gem-cutting potential. Verified locality documentation and cutting potential further elevate collector demand.
Naming history
The name Tourmaline 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 Tourmaline specimens
Black Tourmaline Crystal on Matrix, Namibia
Black Tourmaline and Green Fluorite Cluster, Namibia
Black Tourmaline Schorl X-Shaped Cluster
Black Tourmaline with Smoky Quartz Matrix
Black Tourmaline in Feldspar Matrix, Namibia
Black Tourmaline Schorl Crystal – China
Black Tourmaline (Schorl) – Raw Crystal – China
Black Tourmaline (Schorl) Cluster – Yunnan, China
