Feature
Gems & Gemology, Spring 2002, Volume 38, No. 1

Liddicoatite Tourmaline from Anjanabonoina, Madagascar

Peer Reviewed Article
Dona M. Dirlam, Brendan M. Laurs, and Federico Pezzotta, William B. (Skip) Simmons

Liddicoatite, a calcium-rich lithium tourmaline, was recognized as a separate mineral species in 1977, and named in honor of Richard T. Liddicoat. Most of the remarkable polychrome tourmalines with varied geometric patterns that are characteristic of this species were produced during the 20th century from the Anjanabonoina pegmatite deposit in central Madagascar. To best display its complex color zoning and patterns, the tourmaline is commonly sold as polished slices or carvings. Liddicoatite exhibits physical and optical properties that overlap those of elbaite, so quantitative chemical analysis is required to distinguish these species; both may occur in a single crystal. The most common internal features are color zoning, strain patterns, partially healed fractures, feathers, needle-like tubes, negative crystals, and albite inclusions.

DATA DEPOSITORY

Table 1: Samples from Madagascar
Table 2: Samples from Localities Other Than Madagascar
Submitted by Brendan Laurs
May 17, 2002
Notes: These tables provide all of the chemical data on liddicoatite-elbaite tourmaline that were obtained for this article. The references cited in the table are listed in the reference list of the original article.

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