25 
MINERALOGY, 
s. Pure Selenites. 
A Tranfparent, Spatum Gypfeum diaphmuml 
a, Colourlefs, from Swifferland. 
h. Yellowilha from Mont-martre near 
Paris, 
2. Spar like Gypfum, Marmor metallicuml 
This ftone, on account of its heavinefs^ 
which conies near to that of tin or iron, is 
fufpe6ted to contain fomething metallic ; but, 
as far as is hitherto known, no one has yet 
been able to extrad: any metal from it, im- 
lefs fome traces of iron, which is no more 
than what all other gypfa contain. 
A, Semitranfparent, Spatum Bononienfe^ the 
. Bononian ftone or phofphorus. Its ipeci- 
fic gravity is 4,500 : lOOOj. 
B. Opaque. 
a. White, 
h, Reddiih, are found in Wildeman, at 
Hartz, and in other German mines. 
3. LiverRone, fo called by the Swedes and 
Germans See Sed. xxiv. 
^ Mr. MargrafFhas publifhed fome curious experiments in 
the Memoirs of the Academy at Berlin, about the quality 
thefe fpars have to yield a phofphorus ; and has Ihewn, that 
every gypfeous earth is ht for it, provided metallic particles 
are not predominant in it : now, as the Bononian fparj 
which is ponderous, is of this fpecies, and is the molt lit to 
be brought to a phofphorus, it is evident, that no metallic 
mixture is the caufe of its weight. Mr. Scheffer, in the Me- 
moirs of the Academy at Stockholm, for the year 1753, has 
communicated fome experiments upon a ftone of this kind 
from China, v/hich prove that it perfedlly agrees with the de- 
feriptions given in feveral books, of a ftone called ?etuntfe 
by the Chinefe, and which, it is faid, is ufed in their China 
manufaclories. The phofphorus of Baldwin illuftrates Mr. 
^.dargraff’s experiments. The phofphorefcent quality' of 
^hefe ftones is, however, different from that of the fparry 
iimellones 
