Rocks {mineral} have definite chemical composition. People know properties of 2000 minerals. Main elements in rocks are oxygen 48%, silicon 28%, aluminum 8%, iron 5%, sodium, magnesium, sulfur, and calcium. Together, they are 98% of crust.
types
Elements make pure minerals, like gold and copper. Sulfides, selenides, tellurides, arsenides, antimonides, and bismuthides are similar. Halides are similar. Oxides and hydroxides are similar. Carbonates, borates, and nitrates are similar, but borates and nitrates are rare. Sulfates, tellurates, chromates, molybdates, and tungstates are similar. Phosphates, arsenates, and vanadates are similar. Silicates are similar and include nesosilicates, sorosilicates, cyclosilicates, inosilicates, phyllosilicates, and tektosilicates.
color
Rocks have color and color under fluorescence.
crystal form
Most rocks are crystals {crystal form}, such as cubic crystal, with definite geometry.
density
Rocks have definite specific gravity, depending on composition and crystal structure.
homogeneous mineral
Most minerals {homogeneous mineral} are the same throughout, but bauxite, sand, granite, and porphyry are not homogeneous.
melting
Most rocks have exact melting points, but glasses, resins, and colloids have melting-point ranges.
particle size
Minerals have particle sizes. Clay has fine, cohesive particles. Silt has cohesive particles. Sand has grains. Gravel has small rocks.
refraction
Rocks have definite refractive index.
Physical Sciences>Earth Science>Mineral
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Date Modified: 2022.0224