Definition
Trachyte is a grey fine-grained volcanic rock which mainly consists of alkali feldspar
Picrite is a variety of high-magnesium olivine basalt that is very rich in the mineral olivine
History
Origin
-
Hawaii Islands
Discoverer
Alexandre Brongniart and René Just Haüy
Unknown
Etymology
From Greek trakhus rough’ or trakhutēs roughness
From Greek pikros bitter + -ite, 19th century
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Family
Group
Volcanic
Volcanic
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock