Tourmaline 27,69ct

Tourmaline

Although it has been known since ancient times in the Mediterranean region, the Dutch began importing them in 1703 from Sri Lanka. They named it Sinhalese "Turamali" - stone with mixed colors.

A very characteristic feature of tourmaline is the readiness with which it becomes electrified. By heating and subsequently cooling, as well as applying pressure, e.g. by rubbing, a tourmaline crystal will become electrically charged. It will then attract dust particles and small pieces of paper (pyro and piezoelectricity).

(Ca,K,Na)(Al,Fe,Li,Mg,Mn)3 (Al,Cr,Fe,V)6(BO3)3(Si,Al,B)6O18(OH,F)