Note 4 — THE GATHERER.
Reading edition
Footnote 4
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(return)
The pink topaz is made from the yellow, which, when of intense colour, is put into the bowl of a tobacco pipe, or small crucible, covered with ashes or sand: on the application of a low degree of heat, it changes its colour from a yellow to a beautiful pink. It contains fluoric acid, which may be the means of this change.—Mawe.