BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 

 Vol. 10, pp. 21-26, PLS. 1-2 January 31, 1899 



TOURMALINE AND TOURMALINE SCHISTS FROM BELCHER 



HILL, COLORADO 



BY HORACE B. PATTON 



{Read before the Society August 23, 1898) 

 CONTENTS 



Page 



Introduction 21 



First locality : Tourmaline as a vein mineral. 22 



Second locality : Tourmaline impregnating schist at contact with a large peg- 

 matite vein i 23 



Third locality : Tourmaline impregnating schist at contact with small pegmatite 



veins 25 



Discussion as to origin of these tourmaline rocks 25 



Summary 26 



Introduction 



Tourmaline is a not uncommon mineral in the northern part of Jeffer- 

 son county, Colorado. It is to be found as an ingredient of the quartz- 

 feldspar boulders which strew the mesas bordering the foothills west of 

 Denver and in the beds of the streams which drain the crystalline schists 

 of these foothills. It may also be found in place in the numerous peg- 

 matite veins that everywhere cut the schists. Beautiful lustrous black 

 crystals, often two or more inclies in" diameter, have been obtained from 

 these pegmatite veins. In rare cases colors other than black may be 

 seen, as for instance, some small crystals, about a quarter of an inch in 

 diameter, with white centers and black margins, fpund in a pegmatite 

 boulder near Golden. 



While the pegmatite veins may well be considered the habitat of the 

 Jefferson County tourmalines, in some cases this mineral occurs with 

 somewhat different association. On the so called Belcher Hill road, one 

 of the roads leading from Golden to Central City, are several unusually 

 interesting occurrences of tourmaline. 



This road runs north from Golden, skirting the foothills for a distance 



IV— Bull. Geol. Soc. Am., Vol. Id, 1898 (21) 



