354 



NEW PITCIILIKE lEOJJ ORE« 



New and rare 

 mineral from 

 Kerber's collec- 

 tion. 



called by him 

 pitchlike iion 

 ore. 



Other minerals 

 similarly- 

 named. 



Its compcnent 

 parts. 



IV. 



On a neti) PitcJiUke Iron Ore^ or Sulphated Iron with Ex-* 

 cess of Base: by Mr, Gillet Laumont, Correspon- 

 dent of the Imiilufe, and Member of the Council of 

 Mines *. 



JVln. Karsten has just sent to Mr. Haiiy a new and very 

 rare species of mineral. Examining the geographical cot- 

 lection of the department of Mines at Berlin, that gentle- 

 man found among the Saxon minerals from Ferber's col- 

 lection, which had been purchased by that department, a 

 small box, labelled by Ferber "Pitchlike iron ore from 

 the mine of Kustbesclieerung near Freyberg." 



In his letter to Mr. Haiiy Mr. Karsten observes, that 

 mineralogists hare confounded the pitchlike iron ore some- 

 times with the black blende of Freyburg, at other times with 

 the oxidule of uranium, and that latterly Werner has given 

 this name to Ilauy's phosphated m.anganese f . 



Mr. Karsten quickly perceived, that this mineral did not 

 agree with any of those known by this denomination ; and 

 his conjecture was confirmed by Klaproth, who on analysing 

 it obtained 



Oxide of iron _ - - - 67 



Dry sulphuric acid - - _ 8 



Water - - - - - 25 



Its characters. The specific gravity of this mineral was 



100 

 2-144. 



The 



Similar sub- 

 stance from a 

 mine ia Brit- 

 tany. 



specimens sent to Mr. Haiiy are small and very brittle, but 

 Tarying in colour. A piece being heated in the flame of a 

 candle swelled up, fused pretty readily, and became magnetic. 

 I gave a description of a substance much resembling this 

 in a paper on the mines of Brittany, which I presented to 

 the Academy of Sciences in May, 1786. It' was there 

 called " an acid phosphoric martial salt." I brought it 

 from the lead mine of Huelgoat, celebrated for the phos- 

 phates of lead, which I then made known + . It was among 



these 

 * Journal des Mines, vol. xxili, p. 221. 

 t Jameson's Miiieralogy, vol. ii, p. 5G9, 612. C. 

 X 1 obtained at that time from these lead ores four or five per 



cent 



