Crystal
a. Acton, Nagog Hill Rd.(The central gabbro is not a local rock)
b. Acton, Nagog Hill Rd.(The main rock is half feldspar, half grey schist)
c. Carlisle "Fertility Square"
d. Acton (East side of Nagog Hill) Yellow heart.
a.
b.
c.
d.
c. 
