1 Definition
1.1 Definition
Slate is a fine-grained, foliated, homogeneous metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade regional metamorphism
Tephrite is an aphanitic to porphyritic textured, volcanic igneous rock
1.2 History
1.2.1 Origin
1.2.2 Discoverer
1.3 Etymology
From Old French esclate, from esclat (French éclat)
From Greek tephra, ashes from Indo-European base, to burn
1.4 Class
Metamorphic Rocks
Igneous Rocks
1.4.1 Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
1.5 Family
1.5.1 Group
1.6 Other Categories
Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock