17^ 



Outlines ojtlie Mineralogy and Geology 



It is opaque, or slightly translucent at the edges. 



It is amorphous, or crystallized in very compressed imperfect 



sided prisms ; surface smooth, or longitudinally striated, and 



transversely rent 5 the crystals are promiscuously aggregated, 

 and collected into diverging groups. 



The streak is whitish. 



The fracture is parallel, and curved fibrous, promiscuous di- 



verging, 



and foliated with a two-fold longitudinal intersecting 



'^ 



cleavage ; the folia have two directions parallel to the sides of a 

 rhomboidal prism; the fractured surface is often longitudinally 

 striated. 



li is brittle. 



It is easily frangible. 



The fragments are splintery, and indeterminately angular. 



The specifick gravity is about 3.193. 



Chymical Character, 

 Before the blowpipe it fuses into a greenish grey enamel. 



Geological Situation and Locality. 



It occurs massive and disseminated in Carbonate of Lime, at 

 Chelmsford. 



