ANALYSIS OF T«E PYROPHYSALITE. 3J 



XI. • 



JSlinercihgical Description and chemical Analysis of a Stone, 

 called JHyrophysalite : by Messrs. Hisinger and Berze- 



LILS*. 



JL HE colour of this stone is white, or sometimes of a green- Colour, 

 ish white, and occasionally small superficial blue 9pots of 

 filiate of lime may be observed on it. 



It is found in masses, forming oblong nodules, most com- Form. 

 monly of no determinate figure, but sometimes approaching 

 an irregular rhomboid. Hence no exact measure of its an- 

 gles can be taken : though apparently its lateral angles are 

 about 118' and 62° reciprocally. 



Its fracture is unequal, foliated and very shining in one Fracture, 

 direction only, which seems to be that formed by the incli- 

 nation of 90° or 100° to the axis of the rhomboid. It may 

 be cleft, though less decidedly, in two other directions 

 nearly parallel to the sides of the rhomboid. If broken 

 transversely, it has little or no lustre. The fragments are 

 of an indeterminate form, angular, with sharp edges, on 

 which it is a little translucid. They strike fire with steel, Hardness and 

 and are hard enough to scratch glass easily, but are scratch- g ravit >*« 

 ed by quartz. It is difficult to reduce to powder. Specific 

 gravity 3*451. 



The powder of the purest fragments, projected into a hot Phosphores- 

 spoon, emit a greenish phosphoric light, that is but of short cent b y heat - 

 duration. 



Before the plowpipe without any addition it is nearly in- Before the 

 fusible: but if the heat be urged to a high degree, it '^SteJSbST*' 

 ders it white, opake, and its surface is surrounded by small but at a high 

 bubbles, which issue from it hastily, and burst if the tern- JMj*«*to*A- 

 perature be kept up. This is a very decided characteristic 

 appearance, from which the substance has received its 

 name. 



With borax it fuses easily into a colourless transparent Fuses with bo* 

 glass. 



• Annales de Chimie, vol LXVIII, p. 113, May, 1806. 



Vol. XIX— Jan. 1808. D Soda 



