Blue Tourmaline

Blue Tourmaline is the broad term for tourmaline in blue hues, ranging from teal and greenish blue to deep indigo. It includes the classic iron-colored indicolite and, at the rare and valuable extreme, the copper-bearing neon-blue Paraiba tourmaline.

Blue is one of the less common tourmaline colors, which makes well-saturated blue stones desirable. Most blue tourmaline is the lithium-rich species elbaite, with the blue arising from iron (indicolite) or copper (Paraiba).

It typically forms long prismatic crystals and shows very strong dichroism, so the apparent shade can change markedly with viewing direction, an important factor when the rough is cut.

Blue tourmaline forms in granitic pegmatites, crystallizing from boron-rich fluids in open pockets. Iron substituting into the structure produces ordinary blue indicolite, while the much rarer presence of copper yields the intense neon-blue Paraiba type.

The specific shade depends on the coloring elements and their oxidation state during slow crystal growth, with iron tending toward greener or darker blues and copper toward vivid turquoise tones.

Sources include Brazil, Afghanistan, Pakistan, Madagascar, Nigeria, Mozambique, and Namibia, with copper-bearing material from Brazil, Nigeria, and Mozambique.

Look for blue to greenish-blue prismatic crystals with a rounded triangular cross-section and strong lengthwise striations. Hardness is 7-7.5 with vitreous luster, white streak, and no cleavage.

Blue tourmaline shows very strong dichroism, often dark blue down the length and lighter across it, distinguishing it from aquamarine (hexagonal, weaker dichroism) and blue topaz (basal cleavage, heavier). Apatite is much softer at 5.

An unusually intense neon glow suggests copper-bearing Paraiba, which laboratory testing confirms; more subdued blues are iron-colored indicolite.

Blue tourmaline is a prized jewelry gemstone, faceted into rings, pendants, and earrings, valued because blue is relatively scarce among tourmalines. Copper-bearing Paraiba blue ranks among the most expensive colored gems per carat.

It is also collected as crystals and in multicolor specimens. Value depends on the purity and saturation of the blue, clarity, size, and whether it is iron- or copper-colored. Some blue tourmaline is heat-treated to improve the color.

Metaphysically, blue tourmaline is associated with communication, intuition, and the throat. These meanings are traditional rather than scientific.