50 Dr. Mea(Ps Localities of Minerals. 



chnsetts, I had an opportunity of examining the Mineral- 

 ogy of some districts which have hitherto escaped notice. 

 If (he observations; which I have drawn up on this sub(ect 

 are sufficiently interesting to deserve a place in your Jour- 

 nal, they are much at your service. 



Yours very respectfully, 



WM, MEADE. 

 Prof. Silliman. 



On visiting Worcester, Massachusetts, I met with a Spe- 

 cimen in the Cabinet of William Lincoln, jun. Esq. which 

 attracted my notice This promising Mineralogist was po- 

 lite enough to accompany me to the place where it was ob- 

 tained, and where I procured sufficient to ascertain that it 

 was Vesuvian or Idocrase of Haiiy. The Character of it 

 is as follows. 



It occurs in Groupes and in Cavities, seldom imbedded, 

 massive or crystalized; form, a short rectangular four sided 

 Prism, more or less truncated on the lateral edges so that 

 some of, the crystals are distinctly eight sided. The ter- 

 minations are planes; the sides of the crystals are generally 

 deeply striated so as to resemble the Egerine of Werner. 

 Colour brown, lustre brilliant, translucid, some of the 

 crystals are imperfectly transparent, about the hardness of 

 quartz, easily fusible with intumescence into a transparent 

 glass. It is accompanied by small pale green crystals of py- 

 roxene, and beautiful small garnets of a wine yellow colour, 

 crystalized in rhomboidal dodecahedrons. The matrix of 

 all these appears to be a compound rock containing a mix- 

 ture of massive Garnet,P\roxene, and Idocrase. The Cav- 

 ities are lined with Calcareous Spar in which the crystals of 

 Idocrase of about one fourth of an inch in length appear to 

 be set; b} submitting the Carbonate of Lime to the action 

 of dilute Nitric acid, beautiful and distinct Crystals of Ido- 

 crase and of Garnet can be obtained. 



From the above description I think there can be no hes- 

 itation in calling this mineral Idocrase. It is found in 

 abundance in the neighbourhood of Worcester in a primi- 

 tive rock, but the best specimens are obtained from the 

 stone walls where the crystals are very distinct, in conse- 

 quence of the weakened^state of the stone, which exposes 

 the cavities and leaves the crystals unaltered; this is very 

 much the case with respect to other minerals particularly 



