TOURMALINE
Tourmaline
Tourmaline group
A mineral group with a rich color range. Some individual crystals display several colors together.
GEM PROFILE
Basic properties
- Mineral or material
- Tourmaline group
- Main chemical composition
- Boron-bearing silicates; composition varies by species
- Crystal & structure
- Trigonal
Prismatic crystals often have lengthwise striations and a roughly triangular cross-section.
- Typical colors
- Red, pink, green, blue, yellow, colorless and multicolored
- Mohs hardness
- 7–7.5
A measure of scratch resistance, distinct from resistance to impact or breakage.
About hardness and durability - Representative sources
Examples of known sources. Determining the origin of an individual stone requires examination and comparison with reference material.
- Common cutting styles
- Rectangles, ovals and cushions are common. Multicolored crystals may be cut to showcase the color arrangement.
Explore cutting styles
LOOK A LITTLE CLOSER
What to observe
Pleochroism can change color strength according to crystal direction. The name Paraíba is used for some vividly blue-to-green tourmalines containing copper.
TREATMENT & CARE
Treatments & care
Treatments & identification
Heating, irradiation and fracture filling may be encountered. Variety names, treatments and geographic origin should be considered separately.
Everyday care
Avoid ultrasonic or steam cleaning. Use lukewarm water and mild detergent and protect the stone from high heat and sudden temperature changes.
Cleaning depends on treatment, inclusions and mounting. If a stone's condition is unknown, ask your jeweler or a gem specialist before cleaning.
READING & REFERENCES
References
Public sources for learning about this gemstone's general properties.
- GIA · Gemological reference
- GIA · Care & Cleaning
- Handbook of Mineralogy · Mineral data (PDF)
- GIA · Gem sources and fundamentals
This dictionary provides general educational information. Values are representative and do not identify or grade an individual stone. Locality examples include historical deposits.
Sources checked: October 19, 2026