40 Geology and Mineralogy of a part of Massachusetts, &c. 
tionsof it, polished, would be very beautiful. This may 
be agatejasper. Jameson. 
The crystals of quartz in the mine at Southampton often 
project froma base of agate. ‘The bands are zigzag, like 
those in fortification agate, and seem to be quartz of different 
colours, or quartz passing into chalcedony, often beautiful. 
2. PIBROLITE ? 
Beket. This mineral is in minute fibres, harder than 
quartz, dark coloured, infusible. Occurs only in small 
quantities, and is nearer Fibrolite than any thing I can find. 
Oe CYANITE. 
In mica-slate in Chester, quite common. A darker 
variety than the common is in dark mica-slate, generally 
in single prisms. Emmons. Also in Blanford and Granville. 
This mineral is abundant in this section. Occasionally it 
is disintegrating, and is recognized with difficulty. 
4. STAUROTIDE, 
Very common in the towns about Middlefield. Prisms 
sometimes three inches long; and with Cyanite and Gar- 
net, it constitutes the greater part in some mica-slate. Em- 
mons. Also in Sheffield, Salisbury, &c. 
5. TOPAZ? 
In Middlefield, connected with serpentine are very small 
erystals or fragments, some of them prismatic, and tetrae- 
dral, of a yellow colour, brittle, and harder than rock crystal. 
Unless they are an uncommonly hard variety of yellow 
quartz, they are topaz, which they much resemble. ‘They 
lie loosely in an earthy ground of some disintegrated mine- 
rals. 
