C 779 3 
Luftre. Pearl is valued becaufe of if s Figures and 
culiar Brightnefs not to be imitated. 
Thefe Scones are of the Telle kind, that is, not ta be 
calcin'd by fimple Fire whereas mod other figured 
Stones are calcic ble with a very eafie Fire. 
Thefe Stones «« ~, as I faid, naturally polifli'd and ve- 
ry hard and (olid, and do not confifl: within of Lamina 
or Flakes, but brake every way with great Difficulty, 
and naturally throughout fmooth. 
As for their Figure, it comes neareft that of the Om* 
tri<e ; and many of them are very Qmlritz in fliape, 
Other tranfparent Omhrice I have feen, which yet are ei- 
ther very Flints, or of a flaky and foft Contexture, of the 
nature of Selenites ; and futh are to be found about Filo* 
Ariggs, a noted Set of Rocks near Scarborough. 
As thefe Stones are of a Very different Nature and 
Texture from all other Omlria I ever yet faw, and ha- 
ving no Vefligia of any Spina in any part, of them, h 
may reafonably enough conclude them to be Stones of 
their own kind : And they are in ihape like fome of the 
Omhrice,, yet for the Reafons above- {aid, they will* not; 
come, I think, within the fufpicion of having been Ani- 
mal Subftances. 
For the reft, I am not averfe to think, after fo mani- 
feft and confiderable Difeoveries of this kind, as Augv*. 
fiino S cilia had made in Sicily, that moft of the Omhrice 
have been Echini ; and yet fome of the Prickled, which 
Naturalifts have hitherto called Lapides Judaici, may 
have belonged to fome of thofe Omhiria. But! perfwade 
my felf it will never be found , that any of them have 
ever belonged to any of the Stones in the prefent Ta- 
ble. 
I fliall conclude with one Remark, and that is, to 
incite the Induftry of the Curious , to a more narrow 
fearch into thefe matters, There are but two or three 
Echini yet difcover'd, either in ours or the Msd'awr&wm* 
Sea.,- 
