1 Definition
1.1 Definition
Ijolite is an intrusive igneous rock which is composed mainly of nepheline and an alkali pyroxene, usually aegirine-augite
Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers called coal beds
1.2 History
1.2.1 Origin
1.2.2 Discoverer
Unknown
John Peter Salley
1.3 Etymology
From the first syllable of the Finnish words Ii-vaara, Iijoki, &c. commonly used geographical names in Finland, and the Gr. Xiflos, a stone
From the Old English term col, which has meant mineral of fossilized carbon since the 13th century
1.4 Class
Igneous Rocks
Sedimentary Rocks
1.4.1 Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Soft Rock
1.5 Family
1.5.1 Group
1.6 Other Categories
Coarse Grained Rock, Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock