MINERALOGY, 
119 
SECT. CX. 
2 . Sparry Zeolites, Zeolites fpatofus. 
This refembles a calcareous jpar, though it 
is of a more irregular figure, and is more 
brittle. 
a. Light red, or orange-coloured, from Nya 
Krongrufvan, one of the gold-mines at 
Adelfors, in the province of Smoland. 
ever, for thefe experiments none but the pureft pieces have 
been picked, fuch as have been examined through a magni- 
fying-glafs, and been judged as free from heterogeneous 
mixtures as poffible. It is to be wiihed, that thofe who have 
a fufficient quantity of this done would continue thefe expe- 
riments, in order to difcover what fubftance it is that makes 
this biue colour, which is fo conftant in the hre, fince it can- 
not depend either on copper or iron ; for though thofe metals, 
©n certain occahons, give a blue colour, yet they never pro- 
duce any other but what inftanily vanifhes in the fire, and is 
deftroyed by means of an alcali. What is mentioned in fe- 
veral books about the preparation of the ultramarine from 
filver, can by no means be objeded here, lince in fhofe pro- 
ceffes the filver employed is mixed with copper, and other 
fubfiances, which contain a volatile alcali, whereby the blue 
colour is produced p- 
Jn regard to the above-mentioned qualities of this fione, it 
cannot be clafied under any other kind of earth than this. 
t Mr. Margraf has finre, in his Chemical DilTertatlons, printed in 
German in the year 1761, publlfhed fome experiments on the lapis lazuli j 
and in the chief agrees with our author, without, however, knowing any 
thing of thefe his experiments. Mr. Margraf alfo proves that there is no 
copper in this ftone j and befides tells us, that he has found both a cal- 
careous and a gypfeous fubftance in it, although he took care to pick out 
only the very pure bits for his experiments However, T am led to imagine, 
that the calcareous fubftance is not efien'.ial to the cxiftence of the lapi# 
lazuli, fince Mr. Cronftedt cxprelly ftys, that the ftone he tr^ed did not 
ferment at all w’ith acids. fJe farther mentions this remarkable circum- 
ftance, which makes it ftill more evident that the lapis lajtuli belongs to 
the zeolites, viz. that, when calciiied and riiflblved in the acids ef vitriol, 
of common fait, and of nitre, it turned all thofe acids into a jelly* 
However, he does not take any notice of its containing any becaufe he 
did not profecute his experiments fo far on that point j but fome of bis 
experiments, neverthelefs, feem to indicate, as if all forts 'of lapis lazuli did 
not contain filver, E. 
I 4 SECT. 
