JEAN-CLAUDE REVY, ISM / SCIENCE PHOTO LIBRARY JEAN-CLAUDE REVY, ISM / SCIENCE PHOTO LIBRARY
Calc-alkali granite rock sample. Granite is an igneous rock, one that formed from the cooling of molten rock. Granite is mostly silica (silicon dioxide) and aluminium oxide, with traces of other chemicals. The aluminium silicate minerals are known as feldspars, and can be either alkaline or acidic, depending on the proportion of potassium (alkali), sodium (neutral) and calcium (acidic). Calc-alkali refers to a mineral towards the calcium end of this scale. This is a polished sample of granite, with medium-sized crystals providing the colour and pattern. Granites like these are used as ornamental stonework for buildings, such as for kitchen surface. This sample is 12 by 7.7 centimetres in size.
Model release not required. Property release not required.