This is one of the few tourmalines in the collection that I have had adequately tested, enough, to determine that is not Elbaite, but Liddicoatite. Liddicoatite and Elbaite are very closely related species in the group of minerals we call tourmaline. The only important difference between the two is Liddicoatite has calcium as its principle alkali metals component (in the x location) while Elbaite has sodium. It is impossible to tell them apart by color or crystal shape.
That said, this larger oval is something of a loner by eye. It has a great moderately dark tone value along with a great rose color in my yellowish light source. Under different daylight conditions it kind of gets mixed up with orange. I could even see a color shift effect from different, redder lights, in the office, which they put in to make us feel warmer.
The gemstone has great transparency and is not zoned at all. That is an important point about zoning, because a great deal of Liddicoatite has strong color zoning and the name has become associated with the kind of tourmaline with many color areas. This association is more for the selling of tourmaline than an accurate way to describe Liddicoatite. Few pieces are actually tested, just like the trade came to judge brownish tourmaline, dravite, without chemical testing. (most brownish gem quality tourmaline is Elbaite).
This unique gemstone is both eye clean and bright for a larger darker stone. It weighs 12.46 carats and was made deeper by the use of three wide steps on the crown.