BD why is Tourmaline more expensive if the gravity is lower than that of Rhodolite and the hardness is almost the same?
This is a good one... It gets worse: tourmaline is 'duller' than garnet (lower RI). It even is obvious in the picture of the two rings - perhaps less in person since the stones are small, but the image is magnified...
Now, I think there is a very good reason for the prices given the 'average' tourmaline and garnet. Tourmaline looks GREAT in larger stones - they keep the cheerful color in most lights, while garnet is inevitably dark when large (if there are exceptions, they are few and far between).
The finest red tourmaline might tout 'stop-light red' (hence the name 'rubelite' - hailing of ruby), the finest garnet might pretend, but... no mistake. Hei! low priced ruby is even accused of looking like 'garnet' - none could be downgraded for looking like 'rubelite' (that would be preise - odd, but true).
One hem book does a superb job explaining these 'idiosyncrasies' of gem prices - Richard Wise's. Especially the intro (it has a chapter about gem preciousness in general - a real treat, IMO). Might even be online, that chapter (www.secretsofthegemtrade.com
). It was such a treat to read this one, it remained one of the 3-4 books I absolutely love to talk about. There is 'Ruby & sapphire' and Gubelin's 'Lore of Colored Stones' (or something)... Still, 'value' and prices doesn't make such a clear presence in any other book about precious stones but Wise's, and that was bound to be music to the economics-trained ears. I am still in love
(as you gal's can see).
[gee... 'wrote this, not sure if Richard actually wants 'fan mail' as cheesy as this!]