Dr. Meade^s Localities of Minerals 51 



the Made or Chiastolite of Stirling and the staurotide 

 at Northampton and Winthrop, where fine Crystals can on- 

 ly be procured by long exposure of the Matrix to the action 

 of the Atmosphere. 



Though Vesuvian or Idocrase is generally found in Vol- 

 canic Rocks and has been at one time supposed to be pe- 

 culiar to them, yet it is now well ascertained that it occurs 

 in primitive Rocks also in Norway, Piedmont, and other 

 places. There can be no question with respect to the 

 primitive formation in which these specimens are found 

 near Worcester, but as 1 believe it is the first instance 

 where it has been observed in this Country it is worth no- 

 tice. A mineral of a green colour has been observed at 

 Franklin near Sparta, which some Mineralogists here have 

 called Idocrase; it will however, I suspect, be found to be 

 epidote : neither its crystalization or chymical character 

 identify it with idocrase; it is nearly infusible by the blow- 

 pipe, and can only be reduced by an intense heat to a 

 black scoria : this is an essential distinction, as nothing can 

 be more characteristic of idocrase than its easy fusibility 

 with intumescence into a clear glass ; indeed Mr. Nuttall 

 in his admirable memoir on the mineralogy of Sparta, the 

 first which has appeared on the subject, takes notice of 

 this but calls it epidote though resembling Idocrase. 



Proceeding from Worcester towards Boston I was indu- 

 ced to deviate from the direct road in order to visit Stir- 

 ling where the chiastolite or made is found in such abund- 

 ance. This is perhaps one of the most interesting locali- 

 ties for this curious mineral that has been as yet known, 

 few places afford it in such abundance or in such various 

 forms of crystalization. That which is the most common 

 is described in Cleaveland and the figure 31 plate 4 is a 

 good specimen of it, but the varieties which it assumes 

 would require a much more particular description, as they 

 do not appear to be sufficiently noticed. 



The crystals which are some inches in length, are im- 

 bedded in a dark bluish argillite, and would escape notice, 

 except where the terminations of them appear on the sur- 

 face where the schist has been weathered. It is only by 

 dividing the slate across its natural fracture or cleav- 

 age that the real structure of the Prism can be demon- 

 strated. When a transverse section of the schist is thus 



