188 On the Mineralogy of New York Island. 



dron. Other imperfect crystals, of a pink color, are scattered 

 through the granite rocks near the East river ; some varieties 

 approaching cinnamon stone, others pyrqpe. In a mass of 

 greenstone rock, near Manhattan ville, I found some garnets 

 forming a drusy coating, varying in color from a greenish- 

 white to yellowish-brown and black, presenting faces of the 

 rhombic dodecahedron, but hot forming perfect or distinct crys- 

 tal's. And in boulders of a reddish-grey feldspathic rock in the 

 same vicinity, were found drusy cavities lined with dark green- 

 ish-grey crystals, precisely resembling aplome garnet, though 

 the characteristic striae were wanting on the faces of the crys- 

 tals, some of which are near a quarter of an inch in diameter. 

 Two or three of the specimens were showy and unique. 



Kyanite is diffused through the gneiss of the island, usually 

 pale in color but sometimes showing good shades of blue or 

 green. The blades are small, and the specimens unfit for the 

 cabinet. 



About two years since I found at the Kipp's Bay quarries a 

 mineral which has been pronounced kyanite, though admitting 

 of doubt as regards its identity with that mineral. It occurs 

 in slender crystals or prisms, generally full of transverse cracks 

 or flaws, is of a beautiful Berlin blue, and seems to pass by 

 imperceptible shades of color into a bluish or greyish-green 

 mineral, resembling tourmaline, or hornblende, in which case it 

 loses its fibrous character, and becomes bladed like rhetizite. 

 It is contained in the feldspar and sometimes in the quartz com- 

 posing granite, and occasionally seems to stain the quartz in 

 which it is imbedded. About a year ago, I noticed the same 

 mineral in some fragments of rock at Harlem, but do not 

 remember to have seen specimens like this mineral from any 

 other locality than this island. 



Black tourmaline is frequently met with in different parts of 

 the island, some handsome and very lustrous, doubly terminated 

 crystals having been found both in the gneiss and the granite. 



The vicinity of King's Bridge has furnished some detached, 



