Complex Twinned Calcite, Sambava, Madagascar

During 2004-2005, a limited find of morphologically complex, multiply twinned, light yellow, gemmy calcite was made in the cavities of a Basalt Quarry in Ambariomiambana, Ambohimalaza Commune, in the Sambava area of Sava, Madagascar. Of interest to fluorescent mineral collectors, these Sambava calcites often show a soft yellow to cream-colored fluorescent response activated by organic inclusions. This specimen provides a good example of fluorescent Sambava calcite. This piece measures 47 x 42 x 31 mm, and weighs 33 grams.

Under long wave UV (above), the Sambava calcite shows soft yellow fluorescence.

Under short wave UV, a similar yellow fluorescent response is seen, but not as bright as under long wave UV.

Same specimen, shown under visible light. Note the complex shape of the calcite crystal.