Bicolour tourmaline: how it forms, meaning and crystal care

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Bicolour tourmaline is an elbaite in which a single crystal carries two colours, for example pink and green. The colours reflect changes in the fluid it grew in.

Key points

Colour	two colours in one crystal: pink and green, blue and green, pink and blue, etc.
Mineral family	tourmaline, most often elbaite
Crystal system	trigonal (striated prisms)
Hardness (Mohs)	7 to 7.5
Density	about 3.0 to 3.1
Cause of the two colours	change in the composition of the fluid during growth (chemical zoning)
Known deposits	Brazil (Minas Gerais), Nigeria, Mozambique, Namibia, Afghanistan, United States (Maine, California)
Special case	“watermelon”: pink core surrounded by a green rim
Special feature	pyroelectricity; pleochroism

What is bicolour tourmaline?

Bicolour tourmaline is a crystal of tourmaline (most often elbaite, the species with the widest range of colours) that shows two distinct colours, for example pink at one end and green at the other, or pink at the centre and green on the outside. It is not a separate species: it is an aspect of the crystal. Hardness 7 to 7.5, density about 3.0 to 3.1, trigonal system.

Tourmaline is a mineral of very variable composition: it can incorporate iron, manganese, lithium or copper, depending on what the hot fluid it grows in contains. When that fluid changes during growth, the colour changes too, without the crystal stopping: this is zoning. A colour may therefore appear at the base and another at the tip, or successive layers in rings or bands.

Crystals form in pegmatites, rocks with large crystals. Multicoloured tourmalines are mined in Brazil (Minas Gerais), in Africa (Nigeria, Mozambique, Namibia), in Afghanistan and in the United States (Maine, California).

Bicolour, tricolour, watermelon: what is the difference?

Name	Arrangement of the colours
Bicolour	two colours, generally on either side of the crystal (ends or halves)
Tricolour	three successive zones of colour
Watermelon tourmaline	pink core surrounded by a green rim, which looks like a watermelon in cross-section
Inverted watermelon	green core surrounded by pink

The word “bicolour” says nothing about value: a rough bicolour crystal is a fine curiosity, while a cut bicolour stone with a clean division is more sought after. Polished cross-sections of a crystal show its zoning well, like a record of the stages of its growth.

Traditional symbolism

Two colours in a single crystal evoke duality and the harmony of opposites: the heart (pink) and the mind (green), yin and yang. Modern crystal books associate bicolour tourmaline with balance, reconciliation and friendship.

These associations are modern conventions based on the stone's appearance. Tourmaline in general has been known since antiquity under various names, but this meaning is recent. No study has shown any effect on emotional balance or relationships.

Area	Correspondence cited
Chakra	heart (pink and green)
Element	water and earth, depending on the author
Signs	Libra, Gemini (varies)
Keywords	balance, harmony, duality

How to use it

As a collector's piece: a rough crystal, with its striations and zoning, is a very fine display object.
As jewellery: a ring or pendant in cut stone; the hardness of 7 to 7.5 suits it with care (guide).
As a polished slice: a bicolour disc placed against the light.
In meditation: look at the boundary between two colours and think about something that can coexist with its opposite (tutorial).

Cleaning and cleansing

Cleaning: lukewarm water, mild soap, soft brush.
Sun: avoid prolonged exposure for pink or red colours, which can fade in strong light.
Knocks and heat: rough crystals are fragile at their ends and crack easily; avoid thermal shocks.
Dust: tourmaline is pyroelectric and can attract dust.
Symbolic cleansing: smoke, sound, moonlight (guide).

Recognising a genuine bicolour tourmaline

Sign	Natural bicolour	Watch out for
Boundary between the colours	more or less sharp, often irregular, within the mass	line too sharp on the surface: glued or painted join
Rough crystal	lengthwise striations, rounded triangular section	smooth cylinder: glass or resin
Interior	fractures, inclusions	round bubbles: glass
Price	modest for a rough crystal	very low for a large clear stone: glass

Cut tourmaline may have been heated or irradiated to change its colour; treatments must be disclosed. Some cut stones are assembled from two pieces of different colours; such assemblies are not natural bicolour. See how to read a treated-stone label, real or fake stone and our commitments.

How to choose

For a collection, choose a crystal that is clean, striated, with clearly separated colours, and free of through-fissures. For jewellery, a clean cut stone with both colours easily seen is ideal, but more expensive. Small rough crystals are affordable.

Pairings: with indigolite, green tourmaline and watermelon tourmaline, for a collection of coloured tourmalines. To care for all your stones, read our guide.

Frequently asked questions

Why does tourmaline have several colours?

Because the composition of the fluid in which it grows changes: the crystal then incorporates other elements (iron, manganese, lithium) and its colour varies by zones.

Is bicolour tourmaline always natural?

Most often yes for a rough crystal. Cut stones may be assembled or treated; ask for the disclosure.

What is the difference between bicolour and watermelon?

Watermelon is a special case: a pink core surrounded by a green rim. Bicolour is a more general term for two colours side by side.

Is bicolour tourmaline hard?

7 to 7.5 on the Mohs scale: it withstands daily wear with care.

Why are tourmaline crystals striated?

Striations parallel to the length are a feature of the growth of trigonal crystals. They help identify them.