Buying Tourmaline and Determining Tourmaline Gemstone Value

Tourmaline Color

Tourmaline can occur in a wide range of colors from colorless to black. Black tourmaline is actually the most common color occurrence. Most tourmaline gemstones display two or more colors in a single stone (or two tones of the same color).

Tourmaline Clarity and Luster

Tourmaline is typically transparent to translucent. Opaque material is common for cat's eye tourmaline and schorl. According to GIA, most tourmaline is 'Type II' material in regard to clarity, which means tourmaline is often included. The level of inclusions can vary depending on the type of tourmaline, with some colors being more heavily included than others.

Tourmaline Cut and Shape

Tourmaline 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. Due to the strong pleochroism of tourmaline, lighter colored tourmaline is typically oriented with the table facet perpendicular to the main axis, in order to display the richest hue.

Tourmaline Treatment

Most tourmaline is completely untreated. However, some stones may be heated to improve color and clarity. Yellow, pink and red varieties of tourmaline may be irradiated to enhance color, although irradiation is nearly impossible to detect and does not normally affect value. Heavily included rubellite and Paraiba tourmaline may be clarity enhanced.