Sri Lanka, gems

Gübelin describes four unusual gem materials from Sri Lanka, presenting their physical properties: a saturated blue sillimanite resembling sapphire or cordierite; a yellow-brown epidote whose color is attributed to iron; a warm-brown idocrase (vesuvianite), somewhat more yellow than comparable material from Canada and Kenya; and a red stone initially believed to be taaffeite but subsequently recognized as a distinct mineral of the taaffeite group, provisionally called “taprobanite.” The paper was presented at the 17th International Gemmological Conference at Idar-Oberstein in September 1979.