Tourmaline is usually hewn from a pillar of trigonal crystal, where the stone of different colours are arranged in layers radiating from the middle axis. The most valuable tourmaline comes in bicolour, that is to say, they come from the parts where the different colours meet. Tourmaline from these tumultous regions would feature much inclusions and imperfections, making it a stone of action and immediacy, of creative dynamicism, rather than that of a dull eternity, like what diamond pretends to be (diamond is metastable).
Prices of tourmaline in Colombo: If I remember correctly, 5 cts sell at US$1500 but go down to 300 bucks after haggling over inclusions.
Yesterday, the group visited a family-run topaz lapidary, where uncut topazes litter the place like sand. They were imported from Mozambique and Brazil and some of them were mined locally at Matale. The lapidary handled the cutting and polishing of the stones and some heat treatment, where a gaudy blue is put into the stone but will fade with time. Topazes are cheap and are sold at eight bucks a carat from the place. Aruna the foreman and the family were our guide, and treated us to bananas.