Mineral auctioneers identify some of their tourmalines as "Liddicoatite" and frequently attach special significance (and cost) to these mineral specimens.

Liddicoatite was first identified as a distinct Calcium end-member specie of the Lithium Tourmalines in 1977 in Dunn, et al. - American Mineralogist, v 62, pp. 1121-1124.  There appears to be a complete solid solution between Elbaite (the Sodium end-member) and Liddicoatite, and your typical gem tourmaline will have some of both of these ions.

Dunn says "There are no obvious or distinguishing differences in the morphology of Liddicoatite when compared with Elbaite."  The only way you can be sure you have a genuine Liddicoatite is to have part of your mineral assayed chemically.  If this has not been done, or an assay has been done but you cannot confirm that the assay is somehow tied to the mineral in question, then you would have no proof that the mineral is Liddicoatite and not Elbaite.