Tourmalines

Tourmaline name comes from the Sinhalese word Thoramalli. Some of the opaque black, white, yellow tourmaline species are magnetic whereas green, brown are diamagnetic. Tourmaline, occurring in more colors and combinations of colors than any other gemstone bluish-black, black, brown, brown-yellow, blue, green, red, yellow, pink, etc. bi-colored and multicolored crystals are also common.

Tourmaline Treatments:-
                                           By heating to 842 - 1202 degrees F (450 - 650 degrees C), color changes can be produced in some tourmalines. Some green tourmaline becomes emerald green; other are lightened. The color of tourmalines which have been changed with gamma-irradiation may fade. - Gemstones of the world, Walter Schumann, 200, p 112

Significant Gem Localities:-

 Some forms of tourmaline are dichroic i.e they change color when viewed from different directions. Tourmaline is mined in Brazil, Sri Lanka, Afghanistan, Pakistan, United States, Tanzania, Nigeria, Kenya, Madagascar, Mozambique, Namibia. 

Tourmaline 7 - 7.5 

WEIGHT PER PIECE OF TOURMALINE
OVAL SHAPE		MARQUISE SHAPE		PEAR SHAPE		ROUND SHAPE		SQUARE SHAPE
SIZE	WEIGHT	SIZE	WEIGHT	SIZE	WEIGHT	SIZE	WEIGHT	SIZE	WEIGHT
5*3MM	0.23	5*3MM	0.18	5*3MM	0.20	1.00MM	0.005	3*3MM	0.11
5*4MM	0.34	6*4MM	0.36	6*4MM	0.41	1.25MM	0.008	4*4MM	0.27
6*4MM	0.45	7*5MM	0.63	7*5MM	0.71	1.50MM	0.014	5*5MM	0.52
7*5MM	0.79	8*6MM	1.01	8*5MM	0.88	1.75MM	0.02	6*6MM	0.90
8*6MM	1.27	9*7MM	1.52	8*6MM	1.14	2.00MM	0.033	7*7MM	1.42
9*7MM	1.90	10*8MM	2.17	9*6MM	1.46	2.25MM	0.04	8*8MM	2.12
10*8MM	2.71	11*9MM	2.98	10*7MM	2.02	2.50MM	0.05	10*10MM	4.14
11*9MM	3.73	12*10MM	3.98	12*10MM	4.48	2.75MM	0.07
12*10MM	4.97	14*10MM	5.06			3.00MM	0.09
14*10MM	6.33