Definition
Foidolite is a rare type of coarse-grained intrusive igneous rock with a feldspathoid mineral content greater than 60%
Essexite which is also known as nepheline monzogabbro, is a dark gray or black holocrystalline plutonic Iigneous Rock
History
Origin
-
USA
Discoverer
Unknown
Unknown
Etymology
From the mineral feldspathoid which is the main content of rock
From the locality in Essex County, Massachusetts,US
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Soft Rock
Durable Rock, Hard Rock
Family
Group
Plutonic
Plutonic
Other Categories
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock