Difference between revisions of "Acidic rock"

'''acidic rock''' ([[Category:Noun]][[:Category:Noun|noun]], ''pl.'' acidic rocks; [[Category:Ecology term]][[:Category:Ecology term|ecology term]], [[Category:Substrate term]][[:Category:Substrate term|Substrate term]]) – (1) ''mineralogical'' (''synonym:'' [[siliceous rock]]): a rock with a high content of silica (SiO2 = ''acidic'' minerals); (2) ''chemical:'' a rock with a low pH. ''Note:'' ambiguous term, sometimes imprecisely used to refer only to the pH of a rock [[substrate]]; the mineralogical definition should be preferred because it includes the chemical composition of a rock; if the pH reaction needs to be emphasized it should be referred to as "a rock with a low pH" not as an "acidic rock"; the two definitions are often ''not'' identical, e. g., the ''mineralogy'' of a basalt is ''basic'' because it has a low content of SiO2-minerals, nevertheless a basalt has a low (or neutral) but never a high, "basic" pH. In lichenology the definition has often erroneously been used to refer to [[non-calcareous]] rocks, i. e., rocks without [[calcite]]s (testing negative ("not bubbling") if a 10% solution of HCl is applied top the surface).