Project Description

TOURMALINE

loose tourmaline available to purchase

Tourmaline is the birthstone for October, the gem for the 10th anniversary.

Tourmaline has with superior hardness (7 to 7.5 on the Mohs scale) has the widest range of colours apart from sapphire.

Tourmaline is available in every colour, from colourless to black. It can show every tone from pastel to dark, and can exhibit various colours in the same stone.  Intensity and saturation tend to be the most important factors.

One of tourmaline’s most sought-after and generally available colours is the pink/red variety known in the trade as rubellite.  The more common darker olive tourmalines are much lower in price than fine green tourmaline or brighter bluish green tourmaline which at their best are transparent, brilliant, and clean.  Every shade between green and blue exist from the green with a slight hint of blue to a blue with a slight hint of green to the true blue.  Like green tourmaline the blue colours can be dark to light and strong and vivid or less saturated and grayish. Yellows and purples are more rare.

Paraíba tourmalines in neon blues and greens with their more attractive hues, higher colour saturation, and greater rarity are the most expensive of tourmalines.

Tourmaline is typically transparent to translucent. Tourmaline is often included. The level of inclusions can vary depending on the type of tourmaline, with some colours being more heavily included than others. Green tourmaline is often eye-clean, while blue, red and pink tourmaline, including rubellite, paraiba and watermelon tourmaline, are almost always found with significant inclusions. Cat’s eye tourmaline is usually translucent to opaque and owes its chatoyancy to thin needle-like inclusions.

Tourmalines come in all shapes and sizes. It is often cut into long rectangular bar shapes because of its elongated crystal habit. However, tourmaline is also available in various traditional and fancy shapes and a range of cutting styles.

Tourmaline is strongly pleochroic, which means that it can show different colors when viewed at different angles, one of which is usually much darker than the other. Also many tourmalines absorb more light down the length of the crystal than across it. So a crystal that appears pale green across its length can be very dark green—sometimes almost black—when you look down its length. Depending on the darkness are lightness 0f the rough tourmaline, cutters will orient the cut to achieve the most attractive hue.

Rare cat’s eye tourmaline is cut as a cabochon to best display the desirable cat’s eye chatoyancy. Watermelon tourmaline is often cut into slices to best exhibit its characteristic and attractive colour zoning.

tourmaline jewellery available to purchase

Gemstone Guide