Geochemists study the composition of rocks, minerals, soils, water and the atmosphere and geochemical studies are closely allied to mineralogy and petrology. Environmental geochemistry is important for monitoring and solving problmes of soil, water and atmosphere pollution by noxious waste products. Properties measured include heat-flow, variations of the geomagnetic and gravity fields and electrical conductivity. Seismologists study earthquakes from data recored on seismographs world-wide, with the aim of locating seismically active zones and provide rapid information on earthquakes.
Crystallography concerns the form and internal structure of crystals.
Minerals are identified by their optical properities under and polaristing microscope and from their chemical compositions Gemmology is a study of precious and semi-precious stones such as diamonds, emeralds, and amethyst. The structures provide clues for reconstructing the environments in which they were deposited. Experimental sedimentology attempts to replicate the features of the deposits in order to infer conditions under which they were formed. Sedimentological knowledge is important in predicting the locations underground of sedimentary deposits such as coal and oil. Microscopic fossils are used to date and correlate marine sedimentary sequences.