Stone 11 · Gemstone guide
Tourmaline
Tourmaline group
Tourmaline is a mineral group with an unusually broad colour range. Many jewellery tourmalines belong to the elbaite species, while chemistry, inclusions and treatment can vary across the group.
Gemological register
- Mineral
- Tourmaline group
- Composition
- Complex borosilicate
- Crystal system
- Trigonal
- Mohs hardness
- 7 to 7.5
- Refractive index
- Commonly about 1.624 to 1.644
- Specific gravity
- Commonly about 3.06, with variation
Colour
Colour is a range, not a shorthand.
Tourmaline occurs in nearly every hue and may show two or more colour zones in one crystal. Copper, manganese, iron and other trace elements or colour centres contribute to different appearances.
Clarity and character
Read inclusions in context.
Inclusions vary with colour and source. Pink and red stones may show eye-visible tubes or fractures, while some green material is comparatively clean. Durability must be judged stone by stone.
Treatment disclosure
Ask what changed and how it was detected.
Heating and irradiation can modify colour. Some material may be clarity enhanced, and copper-bearing or geographic-origin descriptions need appropriate testing rather than visual assumption.
Setting practice
The mount answers the material.
The setter maps liquid inclusions, tubes and fractures before applying heat or pressure. Long crystals and pointed cuts need support at their most vulnerable ends.
Care
Care follows the individual record.
Warm soapy water is preferred. Avoid steam, ultrasonic cleaning, high heat and sudden temperature change. Some irradiation-induced colours can be sensitive to heat or prolonged bright light.
Sourcing questions
Questions worth carrying to the desk.
- 01Which tourmaline species or variety is supported by testing?
- 02Has heat, irradiation or clarity enhancement been detected?
- 03If copper-bearing or geographic origin is claimed, is it laboratory supported?
- 04Are liquid inclusions relevant to repair or setting work?
Kundali note
Tourmaline is not part of the standard Navratna group. It may be chosen for colour and design, but that choice is separate from a traditional ratna recommendation.
Traditional association and gemological assessment remain distinct parts of a conversation. No material is presented as an outcome guarantee.
Read the consultation process →Individual assessment
Ask about a stone, setting or record.
Bring the object, report language or sourcing question you want to study. The next step is a direct conversation.
Begin a conversation