MINERALOGY. 45 



to be twins, like the one figured. The cassiterite at Jackson is dark col- 

 ored and opaque, except in the thinnest fragments. The veins are from 

 half an inch to several inches wide, but they are mostly filled with arsen- 

 opyrite, chalcopyrite, and other minerals. The veins are in mica schist. 

 Tinstone has also been found in the town of Lyme, but in much smaller 

 amount than at Jackson. 



32. RUTILE [Ti O,]. 



Rutile has been found at several places in our state. A red, massive 

 variety occurs at Merrimack, on the Souhegan stream; and a considera- 

 ble amount has there been extracted for economic purposes. Crystals 

 have been obtained from the soapstone quarries at Richmond, where 

 many other interesting minerals have been observed. In the rocks ac- 

 companying the limestone at Orford, crystals have been found; also, at 

 the same place, quartz crystals are obtained, which contain acicular crys- 

 tals of rutile! Such quartz crystals were first found in Orford by Dr. 

 Horsford ; but masses and crystals of quartz, penetrated through and 

 through by delicate rutile crystals, have been found at several localities. 

 Handsome specimens have been found near Hanover and at Cornish. In 

 the last named place, a large, smooth, round pebble of quartz, as large as 

 a man's head and filled with little needles of rutile, was found a long 

 time ago, and was broken up and distributed among mineralogists. 

 Rounded pebbles of quartz, with needles of rutile, have been found in 

 the river-bed at Lebanon. These loose pieces may all have been brought 

 from Orford, which lies to the north. The little crystals penetrating the 

 quartz vary from a delicate straw color, when very small, to jet black 

 when larger. Some of the finer specimens are cut as jewels. Lyme, 

 Merrimack, Richmond, and Warren are other localities for rutile. 



The microscope reveals the presence of rutile as a frequent constituent 

 of our granites and schists. It is most often seen in very minute needles 

 piercing the quartz, thus forming microscopic specimens of the same na- 

 ture as the macroscopic ones. These needles are often very long ; and 

 frequently those that appear short will, on changing the focus of the 

 instrument a trifle, be found to go on to surprising lengths. They are 

 often straight and often curved, and almost always in clear quartz. Some- 

 times, with the hand on the thumb-screw, in order to be able to focus 



