Part III.. Of Stones Irregular. 
3*5 
CHAP. VI. 
Of STONES IRREGULAR. 
A S GEMS are chiefly diftinguifhed by their Colours, 
and all other Stones Regular , by their Figures: So 
thefe, by the different degrees of Hardnefs. 
EMERY. Smirk. Of a kind of blackifh Iron-colour. 
The hardeft of unfigur’d Stones. And is therefore ufed 
for the policing and cutting of all Gems, except the Dia¬ 
mond. For the hollowing of flinty Mortars, together with f 
Sand, (a) For the brightening of Armour, and all Metal- j^taRAld. 
lick Equipage. And for Moulds or Forms for the calling 
of Medals and other Coins. Yet Mr. Boyle (b) hath open’d 
it with a Corrofive Menftruum fo far,as to make an infufion p ' 
of Galls therewith to turn blackifh. 
A FLINT of the colour of yellow Amber. It alludeth 
to a Topa%. 
A poliih’d FLINT, not unlike a Calcedony. 
A rough FLINT naturally perforated with feveral large 
Cavities running one into another. It feems to be an aflay 
towards an Eagle-Stone , which is commonly a Flint. 
Flints are oi all colours. Some fo clear, that fome Jew¬ 
elers cut and fell them for BohemicJ Diamonds, (c) They ( jf Eoct ' dc 
are alfo ufed for factitious Geras,with the mixture of Metals, 
in fufion. For making of Glafs. For Mortars for the 
powdering of the Fragments of Geras. And fomctimes added 
to melted Metals, to keep them,as is fuppofed,by the Metal- 
lifts, from (pending, id) in AUrov 01 * 
A BALL of SERPENTINE MARBLE 5 called Ophites, Mu( . Meta ‘ L 
from the winding of the Veins. Near four inches in Dia- 
metre. Ot the nobleft fort; confifting of White, and Red 
or Mtirrey Veins, in Black. 
ANOTHER MARBLE-BALL, two inches and i in Dia- 
metre,Veined,and fpoted with Red,Sand-colour,and White. 
A THIRD, Veined and fpoted with Black,Sand-colour d, 
and White. 
A Ball of ONYCHINE MARBLE,about the fame big- 
nefs 5 on one fide Sand-colour’d, on the other Grey. That 
which is obfervable is this, That inftead of winding Veins, 
Sf 2 it 
