47 



TAB. CCCXXV1IL 



Hornblend. 



Syn. Common Hornblend. James. 1. 357. Kirw. 1. 

 213. 

 Gemeiner Hornblende. Emmerl. 1. 322. 3. 267. 



Hornblend is common in some of our rocks in various 

 amorphous forms. In this specimen, where it occurs in 

 its close, very compact state, it is of a greenish black co- 

 lour ; but as it seems to spread and become less compact, the 

 green hue grows more and more sensible. It is said by many 

 authors in this latter state to form Greenstone with Quartz 

 and Feldspar, or Grunstein of the Germans; but other 

 substances may form Greenstones : hence the necessity of 

 noticing it. Chlorite may be often confounded with it 

 when the Hornblend is divided j but Chlorite is never so 

 dark, hard, or compact as Hornblend, which can with 

 difficulty be scraped with a knife, and composes the darker 

 parts in this specimen. It takes a good polish as well as 

 the white pans, which are hard Feldspar. The green 

 mixture is rather granular and softer, containing Feldspar. 

 This Stone has several conspicuous particles of Sulphuret 

 of Iron, and of Magnetic Iron. It was part of a Boulder 

 from a gravel-pit near York, and may be called an Horn- 

 blend Porphyry with Pyrites and Iron. 



