Part HI. 
Of Gems. 
283 
with Oil and Powder of Diamonds 3 draw it upon the Dia- 
mond, by a Tool, to and fro like a Saw, fo long as is needful 
for that purpofe. 
The BASTARD-DIAMOND. Pfeudo-adamas. Now re- 
maining, as it was found, bred in a Mufculites, a Stone like 
a Mufclejhell. Given alfo by Sir Robert Moray. 'Tis angular, 
pointed, and very clear. And cuts Glafs with great eafe and 
depth. Of our Baftard-Diamonds here in England,thc Cornijh 
are the beft 3 much better than thofe on St. Vincents Rock 
near Briftol. 
CRYSTAL. From ist becaufe fuppofedto 
beonly Water contracted or condenfed with cold. Here 
are feveral forts. 
A CRYSTAL ROCK. In which, feveral lefTer Cry ft ah 
Sexangular, pointed, and moft perfpicuous, grow round 
about a great one, in the form of a Pyramid, above eight 
inches about. The bottom of it being polifh'd , all the 
fides to the top, are very pleafantly apparent through the 
fame. 
A fmall COLUMN of Cryftal, alfo exceeding clear. 
A ROCK of midling Cryftals, growing upon a Semi- 
perfpicuous Bed , or Grey-Mother. They are very clear, 
notwithstanding that beneath they feem to be tincture! 
yellow 5 being there only daubed with fome fubftance of a 
yellow colour. Of thefe Cryftals , the two oppoiite 
fides, are the greatelt : which is alfo obfervable in many 
others. 
A fmall Cryftal COLUMN, with a whitifti Bafe. 
ANOTHER clear Cryftal, growing on a Semiperfpicu- 
ous Mother, together with a kind of Marchafite Spar, or 
teffellated Stone, of an Amethyftine colour. 
A ROCK of fmall Grey Cryftals, almoft like a Calci- 
dony. 
Another of the fame fort, growing upon a kind of Lime- 
fto'ne. 
A Third, with the Points of an Amethyftine colour, 
growing to a Matrix of a purplilh black. 
A Cryftal COLUMN , of an Hyacinthine colour, but 
dilute. An inch in Diametre, and almoft ? a foot longi 
The two oppofite fides of this alfo are the greateft. 
A lefTer one of the fame Species. 
Oo 2 A 
