38. And in a way the petrified Indian reed is not very different in its nature from coral. But this is a subject for another inquiry.
Indian reed itself (ινδικό? κάλαμος), which is described by Theophrastus in his History of Plants,2*3 appears to have been a species of bamboo. The meaning of the term "petrified Indian reed" is very uncertain. The allusion may be to bamboo or some other reed incrusted with calcareous sinter or to a true plant fossil. Among the works ascribed to Theophrastus by Diogenes Laertius284 is a treatise On Petrifactions in two books. This lost work probably contained a systematic treatment of fossils as distinct from ordinary stones and minerals. The final sentence of this section may be an indication that this work was written after the treatise On Stones.
39. Some of these contain gold and silver at the same time, but only the silver can be seen clearly.
Such sulfide minerals as pyrite and galena often contain small amounts of gold and silver as impurities, and galena, which itself is silver-colored, is the chief modern source of silver. Since galena was also the source of the silver at the famous Laurion mines in Attica, it seems very likely that Theophrastus is alluding to it here. There is ample evidence that the citizens of Athens were familiar with the operations at these mines, and it is improbable that a philosopher like Theophrastus, with his special interest in scientific matters, would have had no technical information about the minerals and the processes used at the mines, especially since there was renewed activity in silver mining at Laurion285 during the latter half of the fourth century, when this treatise was written. The metallic appearance of certain natural sulfides is noted by both Dioscorides288 and Pliny.287 Though specific names are given by these authors to some natural sulfides that resemble metals in appearance, there is no evidence that a special name was given to any of these minerals at the time of Theophrastus.
283 IV, ii, 13.
284 V, 2, 42.
285 T. A. Rickard, Man and Metals (New York, 1932), Vol. I, pp. 397-98.
286 V, 115-17 (Wellmann ed., V, 100-102).
287 XXXIV, 121.
