Definition
Chert is a hard, dark, opaque sedimentary rock which is composed of silica with an amorphous fine-grained texture
Borolanite is a variety of Nepheline Syenite and belongs to igneous rocks and contains nepheline-alkali feldspar pseudomorphs which occur as conspicuous white spots in the dark rock matrix
History
Origin
-
Scotland
Discoverer
Unknown
Unknown
Etymology
From flint-like quartz, 1670s, of unknown origin- a local term, which has been taken into geological use
From Alkalic Igneous complex near Loch Borralan in northwest Scotland
Class
Sedimentary Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
Family
Group
-
Plutonic
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock