No. 6. DEPARTMENT OF AGRICULTURE. 407 



various parts of the Cominoiiwealth by farmers and others have been 

 of the same species, varying only perhaps in form. In none of the 

 localities from which these came does tliis mineral appear to exist 

 in deposits of value nor do large deposits of it of commercial im- 

 portance seem to have been found in any part of Pennsylvania, cer- 

 tainly' none have been in the past nor are any being exploited, on 

 a commercial scale, at the present time. Notwithstanding this, there 

 has been no mineral, perhaps, that has raised so many false hopes, 

 and has been so often the foundation upon which so many "Castles- 

 in-Spain" have been erected. 



It has fallen to my official lot and always with a deep sense of 

 regret, if not sorrow, to be obliged to shatter these ''Castles" and 

 to inform the prospectors or senders, that they have been building 

 foundations with sand and that their long cherished hopes of great 

 wealth, if based upon this mineral alone, will not be realized. Men, 

 women and children indulge in fond hopes and one of these is the 

 acquisition, sooner or later, of great financial wealth. If these in- 

 dulgences bring pleasure only, no harm is done and it is even per- 

 haps well that such hopes are entertained rather than gloomy fore- 

 bodings. When, however, it is at the expense of time, money and 

 labor, the disappointment that usually follows is keen, if not bitter. 

 It must not be inferred that this mineral has no value but, on the 

 contrary, it is a very important one. To be commercially valuable, 

 the ore must occur in deposits of sufficient size and purity, at ac- 

 cessible localities, to make its exploitation or mining profitable. 

 Comparatively speaking, the number of such developed deposits in 

 the United States is relatively small, and these are usually found 

 in the crystalline schists of the earliest geological formations. 



To prevent further vain searches and the consequent losses of both 

 money and happiness, it has been thought well to make this mineral 

 the subject of my report for the current year, and to present it in 

 such form, that even those who have little or no acquaintance with 

 Mineralogy will no longer be deceived by it. An attempt, therefore, 

 wdll be made to explain the origin, the occurrence, the uses and the 

 value of this mineral and how to distinguish it from the more valu- 

 able minerals for which it is frequently mistaken, by the layman. 



The mineral referred to is Iron Pyrites or Bisulphide of Iron 

 (FeS 2). It is also known as mundic, a term applied to it by the 

 miners, and as "Fools Gold." The name pyrites, a Greek word, 

 means fire stone. The elder Pliny refers to it in his "Naturalis His- 

 toria," written over eighteen hundred (1,800) years ago; "There is 

 much fire in it." 



It was years ago used in place of flint on fire arms and on tinder 

 boxes. From this, it is seen, that the mineral, under consideration 

 has long since been known and it is quite probable that it has de- 

 ceived, through all these centuries, countless thousands just as it is 

 doing some people at the present time, and all because of its mis- 

 chievous color resemblance to the precious metal gold, and its very- 

 wide dissemination or distribution in rocks of all kinds and of all 

 geologic ages. 



*' ORIGIN 



The origin of and the mode of precipitation of iron pyrites are 

 still, in some cases, questions of doubt. One theory is that iron 

 pyrites result from the action of sulphuretted hydrogen upon salts 



