Dravite is a brown Tourmaline, being a sodium magnesium rich end member of ideal composition
To grow a single crystal of tourmaline you can control the growth on a seed plate by separating the oxide components i.e., using lumps of quartz and alumina etc under isothermal conditions, or by using the temperature gradient method with natural tourmaline as a nutrient. Subsequent to my studies on synthesizing tourmaline from oxide mixes at a later date when I was teaching at Victoria University, Wellington, New Zealand, I did play around for awhile trying to grow tourmaline single crystals. Recently,(45 years later), I have been ratting around in a cigar box of mineral specimens and vials of seed plates and, lo and behold, I found a vial labelled synthetic tourmaline. This coincided with finding my little digital microscope which I hooked up to the computer and proceeded to examine these seed plates from a experiment done ages ago.
I used the temperature gradient method with natural tourmaline as nutrient to try and grow tourmaline on two seed
The first foto shows new black growth on one side of the basal seed plate and hardly any growth on the other side,
Of course, it would take a lot more experimentation to perfect a good method to grow large single crystals of tourmaline, which may be of use in jewellery or for electronic applications. Now-a-days you can buy hydrothermally grown quartz as amethyst and citrine, as faceted gems of 20 carats and costing only $20. How it is possible to do this at a profit is beyond my comprehension. However, I offer this information on the matter in hope that it will be helpful for some student with a thesis on crystal growing. See also Reference (2) of a Russian experiments to grow tourmaline, found on doing a Google search. Also there were two Japanese and one German relevant references. Note that this is real tourmaline and not the "synthetic tourmaline" sold as cubic zirconia or spinel. Allano.
(1) "Synthetic tourmalines containing elements of the first transition series" Journal of Crystal Growth, 1967,1,238-244, by A. M.Taylor and B. C. Terell
(2) "Growth of tourmaline single crystals containing transition metal elements in hydrothermal solutions" Journal of Crystal Growth, 2011, Vol 318, 904-907 by Tatiana Setkova, Yury Shapovalov and Valdimir Balitsky