The first analysis of tourmaline is attributed to A. Wondras-chek.1 Soon afterwards, in the early part of the eighteenth century, analyses were made by Vauquelin and Klaproth. The presence of lithium and boron was not shown until 1818, when Arfved-son2 discovered the former and Lampardius3 the latter. In 1827 Gmelin4 and in 1845 Hermann5 published good chemical analyses of tourmaline. Hermann pointed out for the first time that silica and boric oxide were in definite molecular proportions, four to one. In 1850 thirty analyses were published by Rammelsberg.6 Recognizing the defects of his analyses he revised his paper in 1870.7 From this revision Rammelsberg concluded that all tourmalines were derived from the acid HsSiOs. In 1888 Riggs8 published twenty analyses and proposed as a general formula the simple boro-orthosilicate, R9BO2 · 2SiO4. Penfield and Foote9 showed that this formula reduces to that of Rammelsberg, namely, R6SiO5. Riggs further suggested that there are three tourmaline molecules representing a lithium, an iron, and a magnesium tourmaline, for which he gives formulae.

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