Definition
Conglomerate is a sedimentary rock which forms from rounded gravel and boulder sized clasts which are cemented together in a matrix
Obsidian is a naturally occurring volcanic glass formed as an extrusive igneous rock. It is produced when felsic lava extruded from a volcano cools rapidly with minimum crystal growth
History
Origin
Italy
Ethiopia
Discoverer
Unknown
Obsius
Etymology
From Latin conglomeratus, to roll together, i.e. from com together + glomerare to gather into a ball, from glomus (genitive glomeris) a ball
From Latin obsidianus, misprint of Obsianus (lapis) (stone) of Obsius
Class
Sedimentary Rocks
Igneous Rocks
Sub-Class
Durable Rock, Soft Rock
Durable Rock, Medium Hardness Rock
Family
Group
-
Volcanic
Other Categories
Coarse Grained Rock, Opaque Rock
Opaque Rock