Lemon Calcite 10mmLemon calcite, a type of calcite, is a common mineral found in sedimentary rocks, particularly limestone, and is formed from the shells of dead marine organisms. The "lemon" color of lemon calcite is due to trace amounts of iron or other impurities within the calcite structure. Lemon Calcite was discovered in Pakistan, but can also be found in the Czech Republic, Brazil, Peru, Belgium and the U. S. The rarest forms come from Pakistan. Lemon calcite