Liddicoatite: Vibrant Gem Honors Father of Modern Gemology


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Most liddicoatite comes from Madagascar, including this slice from the Anjanabonoina pegmatite. Coutresy Harvard Mineralogical Museum, photo by Robert Weldon/GIA
Liddicoatite – a calcium-rich lithium tourmaline – is revered for its complex color zoning that often displays several vibrant colors. The common trigonal pattern comes to life when the gem is fashioned as polished slices that highlight the characteristic red, purple, green and yellow hues of this striking gem. Multicolored zoning – what gemologists refer to as parti-colored – occurs when the trace elements change in concentration or composition during a crystal’s growth.

First recognized as a separate mineral in 1977, liddicoatite was named in honor of Richard T. Liddicoat (March 2, 1917 – July 23, 2002), the second president of GIA who is often referred to as the “Father of Modern Gemology.” Dr. Pete J. Dunn and his colleagues from the U.S. National Museum of Natural History identified liddicoatite as a distinct mineral and chose the name in recognition of Liddicoat’s many contributions to gemological knowledge and education, including his creation of the International Diamond Grading System and its well-known and universally recognized scales for measuring the color and clarity of diamonds.

Liddicoatite – along with elbaite, dravite, uvite and schorl – is one of the major tourmaline species. Its appearance is similar to elbaite, and it can only be distinguished through chemical analysis. Most known liddicoatite comes from the Anjanabonoina pegmatites in central Madagascar.