Tourmaline Stone

Tourmaline is a complex cyclosilicate mineral group containing boron and aluminum. Our in-stock inventory specifically features Black Tourmaline, known scientifically as Schorl (NaFe²⁺₃Al₆(BO₃)₃Si₆O₁₈(OH)₄):

• Chemical & Physical Characteristics: Schorl is the iron-rich endmember of the tourmaline supergroup. The dense incorporation of ferrous iron (Fe²⁺) gives it an opaque, deep jet-black coloration with a mirror-like vitreous luster.
• Pyroelectric Physics: Tourmaline possesses pronounced pyroelectric and piezoelectric properties; when subjected to temperature shifts or physical pressure, opposite ends of the crystal develop opposing electrostatic charges. In historical trade, Dutch merchants called it aschentrekker (“ash-puller”) because heated crystals naturally attracted wood ashes.
• Faceted Collection: While black tourmaline is commonly sold as rough or tumbled chips, our collection consists of expertly precision-cut, faceted Oval Mixed Cut gemstones ranging from 3.68 to 5.88 carats. Read our complete Black Tourmaline Guide for gemological specifications.

Black stones frequently mimic one another in jewelry, but laboratory gemologists separate genuine Schorl using diagnostic properties:

• Refractive Index & Birefringence: Tourmaline has a high refractive index of 1.624 to 1.644 with a strong birefringence of 0.018 to 0.020. In contrast, volcanic glass (obsidian) and black glass have much lower, single refractive indexes (~1.48–1.51), while black onyx has a lower chalcedony reading of ~1.535.
• Density & Heft (Specific Gravity): Due to rich iron content, Schorl is distinctly dense, with a specific gravity of 3.10 to 3.25—noticeably heavier in the hand than glass (2.3–2.5) or chalcedony (2.60).
• Crystal Growth Features: Under magnification, natural tourmaline often displays parallel vertical striations along the prism faces and characteristic internal fluid inclusions (trichites), which are absent in molded glass or dyed plastics.
• The Ratna Gems Guarantee: Every Tourmaline stone at Ratna Gems is guaranteed 100% natural, Earth-mined, unheated, and untreated, verified by independent accredited gemological laboratory certification.

Every Tourmaline (Schorl) gemstone sold by Ratna Gems is individually tested and accompanied by an independent accredited gemological laboratory testing report. The certificate identifies the mineral species as Natural Tourmaline, gemstone variety as Natural Black Tourmaline (Schorl), exact carat and ratti weight, dimensions, specific gravity (3.10–3.25), refractive index (1.624–1.644), hardness (7.0–7.5 on Mohs scale), confirms diagnostic borosilicate composition, and verifies untreated natural status. Each report includes a unique certificate number and verifiable QR code for direct verification on the issuing laboratory’s official portal.

Optional International Certification: Every gemstone includes an independent accredited laboratory certificate at no charge. If you specifically require an additional report from GII, IIGJ, or IGI, you can select it directly from the certification dropdown on any product page upon request (official laboratory testing fees apply in advance on a non-refundable basis).

With a Mohs hardness of 7.0 to 7.5 and no distinct cleavage, Tourmaline is exceptionally durable for daily-wear jewelry:

• Scratch Resistance: Harder than window glass and airborne quartz dust, faceted tourmaline maintains a brilliant facet polish and sharp facet junctions over decades of regular wear.
• Thermal Caution: Because tourmaline crystals frequently contain microscopic liquid-gas inclusions (trichites), they are sensitive to thermal shock. Never clean tourmaline with steam cleaners, boiling water, or ultrasonic machines, as rapid heating or ultrasonic vibrations can cause internal inclusions to expand and fracture the stone.
• Safe Cleaning: Wash gently with lukewarm water, mild dish soap, and a soft microfiber cloth or soft toothbrush. Rinse thoroughly and dry with a lint-free towel. Store in a padded jewelry compartment away from harder gems like sapphires, rubies, and diamonds.

Across global lapidary history and classical Indian traditions, historical literature outlines the following customary conventions:

• Customary Metals: Sterling Silver (925 Silver), White Gold, or Platinum provide a striking visual contrast to the deep, lustrous black polish of Schorl.
• Traditional Placement: Customarily worn as a faceted ring on the middle finger (Madhyama) or little finger of the non-dominant hand, or as a pendant resting against the collarbone or chest.
• October Birthstone: Tourmaline is celebrated globally as an official birthstone for October (alongside Opal).
• Historical Context: Revered in traditional lapidary (known in Sanskrit and Hindi texts as Turmali) as an ornamental and decorative mineral.

Please Note: Ratna Gems shares these details solely for cultural and informational awareness for customers seeking traditional jewelry. We sell all gemstones strictly on the basis of verified physical authenticity, mineral quality, and certified origin, and make no astrological, metaphysical, or medical claims.