Just got back from a traditional bookstore that is now half toys and puzzles. I found a few cheap books and looked in the known locations for books on gemstones and minerals etc. And I found a new one which is unusual. It was published in 2012 and tried to cover everything about gemstones for the appraiser. So I sat on one of those provided benches and focused on seeing how an authoritative book, not the regurgitated of the internet, handled tourmaline.
Now I didn’t expect them to get the concept of using dravite both as a name for a gem variety and a mineral/species in the group of related, naturally occurring chemicals, that is called tourmaline. Incorrectly using rubellite for pink tourmaline or indicolite for blue green tourmaline was also expected . But when they failed to even mention Mozambique as a source of tourmaline and that magnesium colors tourmaline yellow/brown, it was too much. To make matters even worse, the statement about magnesium, which can not color tourmaline period, was the only attempt to say which impurities act as chromophores (coloring agents) in tourmaline.
It is easy to say that a couple of pages on tourmaline is not enough to even begin to cover the subject of tourmaline for appraisers or anyone else, but to get as much wrong in so brief an effort is some kind of accomplishment. Paraiba/cuprian tourmaline may have awaken the world to the fantastic potential of tourmaline, but the crop of instant experts on tourmaline, that spent most of the career life dealing with sapphires, rubies etc. should do their homework better before writing about a world they really don’t know that well.
Bruce
