Tourmaline

Tourmaline is a crystal boron silicate compounded by elements aluminum, iron, sodium, magnesium, potassium, or lithium. Although tourmaline is semi precious, once cut; it can rival others that are precious in popularity. The origin of tourmaline is Sinhalese from “tora-molli” — its meaning is unclear.

Tourmaline was introduced to Europe as a curio by the Dutch East India Co. Jet, a mineraloid, and schorl, sodium iron aluminum boro-silicate, were both familiar to Europeans, however, in 1703, tourmaline and schorl were discovered to be the same mineral. 93% of tourmaline deposits are made of schorl.

Quartz and tourmaline are known to be piezoelectric while of the two only schorl is pyroelectric. The variety of tourmaline rivaled zircon, and Ceylon was soon used as a qualifier because heated black tourmaline (schorl) was able to attract or repel burnt ash. By the 19th century, cut and polished tourmaline was used to polarize light.

Tourmaline varieties include verdelite which is Brazilian emerald, indicolite that is blue-green, and rubellite that is pink or red. Multicolored tourmaline crystals reflect changes of chemistry, since all are formed in water, the so-called “watermelon tourmaline” or elbaite. Rubellites have needle-like inclusions which cause chatoyancy, however, rubies and tourmalines are both fluorescent using an UV lamp.

Cabochons are, therefore, the best cut for exhibition.

This makes red tourmaline easier to differentiate from red garnet than red garnet from a ruby. Collectors of red tourmaline (rubellite) highly value any that are clear because their similarity with a corundum. Only a brown tinge of newly found deposits separate the fine quality of older specimens. Thus, region can be a factor.