Definition
Taconite is a low-grade iron ore which belongs to sedimentary rock and containing about 27% iron and 51% silica
Trondhjemite is a leucocratic (light-colored) intrusive igneous rock. It is a variety of tonalite in which the plagioclase is mostly in the form of oligoclase. Trondhjemites are sometimes known as plagiogranites.
History
Origin
Western Australia, Minnesota
Tonale, Italy
Discoverer
Newton Horace Winchell
Unknown
Etymology
From the name of Taconic Mountains in New England
From Trondheim, Norway
Class
Sedimentary Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Family
Group
-
Plutonic
Other Categories
Coarse Grained Rock, Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock