ii6 BOOK V. 



in gold mines, silver mines, or other mines ; nor do other miners neglect them 

 if they are found in stone quarries, or in their own veins ; their value is usually 

 indicated by their taste. Nor, lastly, does the miner fail to give attention to 

 the solidified juices which are found in metallic veins, as well as in their own 

 veins, from which he collects and gathers them. But I will say no more 

 on these matters, because I have explained more fully all the metals and 

 mineral substances in the books " De Natura Fossilium." 



But I will return to the indications. If we come upon earth which is 

 like lute, in which there are particles of any sort of metal, native or rudis, 

 the best possible indication of a vein is given to miners, for the metaUic 

 material from which the particles have become detached is necessarily close 

 by. But if this kind of earth is found absolutely devoid of all metallic 

 material, but fatty, and of white, green, blue, and similar colours, they must 

 not abandon the work that has been started. Miners have other indications in 

 the veins and stringers, which I have described already, and in the rocks, about 

 which I will speak a little later. If the miner comes across other dry earths 

 which contain native or rudis metal, that is a good indication ; if he comes 

 across yellow, red, black, or some other " extraordinary " earth, though it is 

 devoid of mineral, it is not a bad indication. ChrysocoUa, or azure, or verdigris, 

 or orpiment, or realgar, when they are found, are counted among the good 

 indications. Further, where underground springs throw up metal we ought 

 to continue the digging we have begun, for this points to the particles having 

 been detached from the main mass like a fragment from a body. In the 

 same way the thin scales of any metal adhering to stone or rock are counted 

 among the good indications. Next, if the veins which are composed partly 

 of quartz, partly of clayey or dry earth, descend one and all into the depths 

 of the earth together, with their stringers, there is good hope of metal being 

 found ; but if the stringers afterward do not appear, or Uttle metallic 

 material is met with, the digging should not be given up until there is nothing 

 remaining. Dark or black or horn or hver-coloured quartz is usually a good 

 sign ; white is sometimes good, sometimes no sign at all. But calc-spar, 

 showing itself in a vena profunda, if it disappears a Uttle lower down is not a 

 good indication ; for it did not belong to the vein proper, but to some stringer. 

 Those kinds of stone which easily melt in fire, especially if they are translucent 

 (fluorspar ?), must be counted among the medium indications, for if other 

 good indications are present they are good, but if no good indications are 

 present, they give no useful significance. In the same way we ought to form 

 our judgment with regard to gems. Veins which at the hangingwaU and 

 footwall have horn-coloured quartz or marble, but in the middle clayey 

 earth, give some hope ; likewise those give hope in which the hangingwaU 

 or footwaU shows iron-rust coloured earth, and in the middle greasy and 

 sticky earth ; also there is hope for those which have at the hanging or footwall 

 that kind of earth which we caU " soldiers' earth," and in the middle black 

 earth or earth which looks as if burnt. The special indication of gold is 

 orpiment ; of silver is bismuth and stibium ; of copper is verdigris, melanteria, 

 sory, chalcitis, misy, and vitriol ; of tin is the large pure black stones of 



