Schorl is the most common variety of the mineral tourmaline, captivating with its deep, rich black color. This complex borosilicate of sodium, iron, and aluminum crystallizes in the trigonal system, often forming characteristic elongated prismatic crystals with distinct longitudinal striations on their faces. Typically opaque with a distinct vitreous luster, schorl can be translucent in thin fragments. Schorl is a relatively common mineral found in granite pegmatites, metamorphic rocks, and some hydrothermal veins worldwide.
Significant deposits are located in Brazil, Pakistan, Afghanistan, the USA (California, Maine), Madagascar, and various African countries. In Ukraine, schorl crystals are found, notably in the Volyn chamber pegmatite deposit. Thanks to its hardness (7-7.5 on the Mohs scale) and attractive black color, schorl is used in jewelry, primarily for cabochons, beads, or as decorative inlays.
However, it holds particular value for mineral collectors who appreciate its perfect crystalline forms and classic black hue. Historically, schorl has been attributed protective and grounding properties. This stone is believed to promote concentration and stability. It also possesses piezoelectric and pyroelectric properties: when heated or compressed, schorl crystals generate an electrical charge, making it of scientific interest and offering some technical applications.
Schorl is not just a beautiful natural mineral, but also a popular collector's specimen and a material for creating unique jewelry, combining aesthetic appeal with intriguing physical properties.
Physical properties
Chemical formula
NaFe²⁺₃Al₆(Si₆O₁₈)(BO₃)₃(OH)₃(OH)
Hardness
7 - 7.5
Crystal system
Trigonal
Transparency
Opaque, rarely translucent in thin fragments
Luster
Vitreous, sometimes resinous on fracture
Color
Black, sometimes brownish-black, bluish-black
Specific gravity
3.06 - 3.26
Jewelry with this mineral
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