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 - click for larger pic
Hornfels in corner of quarry
© Quintin Wight
Hornfels lines - nepheline - click for larger pic
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".*

Minerals found in hornfels
Aegirine
Albite
Allanite-(Ce)
Anatase
Astrophyllite
Barite
Bastnäsite-(Ce)
Beryl
Beryllonite
Brookite
Calcite
Celestine
Chalcopyrite
Cordierite
Cordylite-(Ce)
Corundum
Dawsonite
Diopside
Dolomite
Donnayite-(Y)
Dravite
Elpidite
Epididymite
Epidote
Eudidymite
Fluorapatite
Fluorite
Franconite
Gaidonnayite
Galena
Gersdorffite
Gmelinite
Goethite
Gypsum
Hematite
Hochelagaite
Hypersthene
Löllingite
Lorenzenite
Magnesite
Marcasite

Mckelveyite-(Y)
Microcline
Molybdenite
Muscovite
Narsarsukite
Neighborite
Prehnite
Pyrite
Pyrrhotite
Quartz
Riebeckite
Rutile
Siderite
Spessartine
Sphalerite
Steacyite
Strontianite
Thorogummite
Vesuvianite
Yofortierite

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