Mineral Environments
- Hornfels -

     "Hornfels, a fine-grained, dark gray, brown or dark green rock resulting
from the metasomatic effect of the intrusion on the sedimentary host rocks,
forms a corona around the mountain from 10 to several hundred meters in
width. Very large blocks of hornfels resulting from slumping of sedimentary
rocks into the magma are also encountered, and are among the major rock
types of the East Hill suite".*

Hornfels in corner of quarry
© Quintin Wight

Hornfels lines and nepheline
© Quintin Wight

     "The most common minerals found in hornfels are calcite, siderite, pyrite, rutile and quartz. Euhedral crystals of pyrite and narsarsukite replaced by vesuvianite are occassionally found in the hornfels".*

* From Mineralogical Record Vol 21, Horváth L. and Gault R.A.