266 



DESCRIPTIVE MINERALOGY. 



The variety Heliotrope is found in veins in the slate in the town of Bloomingrove. It is of 

 a rich grass-green colour, finely translucent, and is susceptible of a fine poUsh. 



In the town of Monroe, two and a half miles southeast of Greenwood furnace, there is a 

 bed of quartz. At the northeast end, where alone it is visible, it is four rods wide, and rises 

 fifteen feet above the gneiss on each side. It is visible for more than twenty rods, and gradually 

 disappears beneath the surface. The quartz is white and nearly opaque, containing in many 

 places green coccolite.* 



Putnam County. Hyalite, of a light blue colour, is found in thin coatings on the granite 

 at the Phillips ore bed. It is rare, and is sometimes associated with green malachite. 



Fig. 165. Rensselaer County. Diamond rock, near the village of Lansingburgh, 



has furnished fine specimens of limpid quartz. Some were well defined 

 and doubly terminated, but most commonly one of the ends was imbedded 

 in the rock. The forms observed here are those represented in Figs. 131 

 and 132. It is now exceedingly difficult to obtain good specimens from this 

 locality, but crystals of various degrees of perfection are not uncommon in 

 the slate in various parts of the county. The form represented in Fig. 165, 

 is common at Williamstown, and may hereafter be found in this and in Co- 

 lumbia county. 



Richmond County. Smoky quartz, as well as the limpid variety, occurs 



in well defined crystals in the hill which passes through this county. It is 



usually in druses of small crystals, and sometimes these radiate from a centre, and exhibit 



perfect terminations on the circumference. The specimens are often so deeply coloured as 



to place them under the ferruginous variety. 



The walls of the thin fissures in the greenstone at Port Richmond quarry, are sometimes 

 studded with small but quite perfect crystals of quartz, associated with equally minute crys- 

 tals of feldspar. 



St. Lawrence County. At the mines of specular iron in the towns of Fowler, Hermon 

 and Edwards, crystals of the forms represented in Figs. 144 and 162, are abundant. They 

 are sometimes two inches in diameter, and are translucent or transparent. They also occur 

 loosely in the soil, when they have a dark colour, are entirely opaque, and somewhat cellular, 

 as if some portion of the material of the crystal has been dissolved out. 



In the vicinity of Gouverneur, smoky crystals are found in the limestone, associated with 

 tourmaline and other minerals. They sometimes exhibit the fused appearance already noticed. 

 On the banks of Laidlaw lake, in the town of Rossie, there is a fine locality of crystallized 

 quartz. The crystals are implanted, grouped, singly and sometimes doubly terminated ; in the 

 latter case, touching the rock only by the faces or angles of the prism. They are from half an 



Horton. NeiB-York Geological Reporti, 1839. 



