BOOK V. 



109 



the earth or stone too far outweighs the gold. A vein which contains a 

 larger proportion of silver than of gold is rarely found to be a rich one. 

 Earth, whether it be dry or wet, rarely abounds in gold ; but in dry earth 

 there is more often found a greater quantity of gold, especially if it has the 



Part Bromyrite 

 (Ag Br) 



Part Cerargurite 

 (Ag CI) (Horn 

 Silver) Part 

 Stephanite 

 (Ag5SbS4) 



Liver-coloured 



silver 

 Yellow silver 



*Grey silver 



*BIack silver 



*Purple silver 



Atgentum rude jecoris Gedigen leberfarbig 



colore . . . . . . ertz . . 



Atgentum rude liUeum . . Gedigen geelertz 



Argentum rude cineraceum Gedigen graw ertz 



Argentitm rude nigrum . . Gedigen schwartz ertz 



Argentum rude furpureum Gedigen braun ertz . . 



The last six may be in part also alteration products from all silver minerals. 



The reasons for indefiniteness in determination usually lie in the failure of ancient 

 authors to give sufficient or characteristic descriptions. In many cases Agricola is sufficiently 

 definite as to assure certainty, as the following description of what we consider to be silver 

 glance, from De Nalura Fossilium (p. 360), will indicate : " Lead-coloured rudis silver is 

 " called by the Germans from the word glass {glaseriz), not from lead. Indeed, it has 

 " the colour of the latter or of galena (plumbago), but not of glass, nor is it transparent 

 " like glass, which one might indeed expect had the name been correctly derived. This 

 " mineral is occasionally so like galena in colour, although it is darker, that one who is not 

 " experienced in minerals is unable to distinguish between the two at sight, but in substance 

 "they differ greatly from one another. Nature has made this kind of silver out of a little 

 " earth and much silver. Whereas galena consists of stone and lead containing some silver. 

 " But the distinction between them can be easily determined, for galena may be ground 

 " to powder in a mortar with a pestle, but this treatment flattens out this kind of rudis silver. 

 " Also galena, when struck by a mallet or bitten or hacked with a knife, splits and breaks to 

 " pieces ; whereas this silver is malleable under the hammer, may be dented by the teeth, 

 " and cut with a knife." 



Copper Minerals. 

 Aes piirum fossile Gedigen kupfer 



Aes rude plumhei 



coloris 

 Chalcitis 



Pyrites aurei 



colore 

 Pyrites aerosols . . 

 Caeruleum 

 Chrysocolla 



Molochites 

 Lapis aerarius . . 

 Aes caldarium 

 rubrum fuscum 

 or 

 Aes sui coloris . . 

 Aes nigrum 



Kupferglas ertz 

 Rodt atrament 



Geelkis oder 

 kupferkis 



Berglasur 



schifergrim 

 Molochit 

 Kupfer ertz 



Lebeter kupfer 



Rotkupfer 

 Schwartz kupfer 



Native copper 



Chalcocite (CU2S) 



A decomposed copper 



or iron sulphide 

 Part chalcopyrite (Cu 

 Fe S) part bornite 

 (Cu3FeS3) .. 

 Azurite 

 I Part chrysocolla 

 ( Part Malachite 

 Malachite 



When used for an ore, is 

 probably cuprite . . 



Native copper 



*Copper glance 

 Chalcitis (see notes 

 on p. 573) 



Copper pyrites 



Azure 



Chrysocolla (see 

 note 7, p. 560) 

 Malachite 

 Copper ore 



*Ruby copper ore 



Probably CuO from 

 oxidation of other 

 minerals . . . . *Black copper 



In addition to the above the Author uses the following, which were in the main 

 artificial products : 



Aes luteum 

 Aes caldarium . 

 Aerisflos 

 Aeris squama . 



Atramentum 

 sutorium 

 caeruleum or 

 chalcanthum . 



Griinspan oder 

 Spanschgriin 

 Gelfar kupfer 

 Lebeterkupfer 

 Kupferbraun 

 Kupferhammerschlag 



Verdigris 



Impure blister copper 



Cupric oxide scales . . 



Blaw kupfer wasser Chalcanthite 



Verdigris 

 ( Unrefined copper 

 1 (see note 16, p. 511) 

 j Copper flower 

 1 Copper scale (see 

 note 9, p. 233) 



Native blue vitriol 

 (see note on p. 572) 



