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Magic Stones and Electric Gems: Theophrastus

Such is the confusion in the statements made by the early Greek and Latin writers as to the emerald, under which generic name they seem to have included almost all green stones of any ornamental or other value, that we cannot absolutely reject the conjecture that Theophrastus (third century B.C.), the earliest of these writers on precious stones, might have referred to specimens of green tourmaline, when he states that the true emerald appeared to have been produced from jasper, as one of the Cyprian specimens was said to have consisted of one-half jasper and the other half emerald, the metamorphosis as yet being incomplete. We admit that if Theophrastus uses the word jasper here to signify the reddish variety, we would have the combination of green and red zones in a single crystal sometimes observable in tourmaline. How this can be reconciled with the previous statement of the same author that the Cyprian "emeralds" which came from the copper mines of that island were chiefly used for soldering gold, and hence seem to have been of the class of mineral called chrysocolla by ancient writers, is, however, not easy to suggest. The so-called Brazilian emeralds mentioned by the Dutch mineralogist, Johann de Laet, as having been found shortly before 1647 in mines near Spiritus Sanctus, may perhaps have been green tourmalines. These crystals were described by Gesner as of cylindrical form, striated, and of a vitreous lustre; their color was like that of the prase and they were transparent. Although De Laet adds the assertion that the Oriental emerald (green corundum) was as hard as the sapphire, the Brazilian emeralds approached more closely to the Oriental in point of hardness than did emeralds from any other source of supply; and green sapphires have never been found in Brazil, while green tourmalines have been.

The earliest published work in which the electric properties of tourmaline are noted appears to be an anonymous or quasi anonymous treatise published in 1707, certain initial letters of the quaint title being italicized to indicate the initials of the author's name. The first scientist to derive the action of the so-called Aschentrekker or "Ash-Attractor" from electric energy is said to have been the great Linnaeus, who bestowed upon the tourmaline the name of the "Electrical Stone."