Gemstone treatment

Heat Treatment, Tourmaline

Heating can reduce brownish, grayish, or overly dark components and improve blue, green, pink, or red appearance. Microscopic detection is often difficult.

01

What to look for

Heating can reduce brownish, grayish, or overly dark components and improve blue, green, pink, or red appearance. Microscopic detection is often difficult.

02

What it means

Heat treatment is used to improve tourmaline color and is often stable. Disclosure is expected when known.

03

Expert move

Color alone rarely proves treatment. Copper-bearing Paraiba-type tourmaline and fine rubellite often need lab documentation for high-value sales.