Of KeguUr Stoner. 
Part III. 
in a like manner, but differently contiguous 3 fo, as in fome 
places, feveral Plates may make but one Refraction $ in 
others, two or more. It was dug out of a very high 
Mountain in IJIand, one whole fide whereof confifteth of 
this Spar. i. 
TWO PIECES of the fame Stone, about two inches and 
a long, broad, and thick. Thus far of Rhomboid Stones. 
The RHOMBICK LEAD-SPAR. Frequently found 
in the Lead-Mines in Derby fhire, and in others. By fome • 
called Englijh Talk, But very improperly. For though 
it confifteth of feveral Plates, yet not flexible, but brittle as 
Glafs. Befides, 'tis not of a Rhomboid, but Rhombiek 
Figure, that is, a Diamond-fquare, or with the Angles un- 
equal, the fides equal. Nor doth Talk feel any Acid, but 
this with Spirit of Nitre is eafily diffolved. It breaks into 
pieces, which, though never fo fmall, yet retain the fame 
Figure. Being burned, it yieldeth a Lixivial Salt. 
A clear FLINT, of the colour of yellow Amber, with 
Stria on the fides (haped into little Rhombes. 
A RHOMB of MUSCOVY-GLASS. This Stone is 
by moft called Selenites. By fomc Maria Glacies. By 
O) Aidrov. Agricola, and Kent man, Magnet is. By Ambrofinm, (a) con- 
Muf. Metaii. founded) un d er the fame Name, with Talk Tis indeed 
the neareft of kin to that of any Stone, being infenfible of 
Acids 3 and confifting of very thin, perfpicuous, glofly, 
parallel, and flexible Plates. Seldom found figurcl. But 
when it is, Ifuppofe always, as it is here in this piece, fc. into 
a Diamond-fquare, L e. with unequal Angles, and equal 
fides 3 whereas in a TalJ^Cryftal, both are unequal. It was 
taken out of Mount Hamus. 
A very white Piece of Mufcovy-Glafs. 
ANOTHER,of a pale Green colour, with a kind of filver 
glofs, and femiperfpicuous. 
Another, of the colour of tarnilh'd Copper mixed with 
black. 
A lump of Selenites. 'Tis immerfed in fmall pieces in 
a whitifh Stone, a little Diaphanous, and fo hard as to cut 
Glafs. 
This Stone grows in Cyprus, Sicily, Saxony, and many 
other places 3 efpecially in Mufcovy, whence the Englijh 
Name. Ufed in Saxony, and other places in Germany, in 
Windows, 
