Citrine is found in igneous (rocks produced under conditions involving intense heat) and metamorphic rocks, particularly in granite and gneiss. It is also found in classic sediments (matter that settles to the bottom of a liquid). Most good crystals are found as gauge minerals in mineral veins. Citrine is often found in association with amethyst, but it is much more rare than its purple cousin. Because it resists weathering, it is also found in alluvial sands and gravels. The largest supplier of natural citrine is the Rio Grande do Sol state in Southern Brazil. Citrine mines in the US are found in Colorado, North Carolina and California. The gemstone is also found all over the world, in Spain, Brazil, Africa, South Africa, France, Britain, Madagascar and the Soviet Union.
Citrine is defined as “a pale yellow quartz resembling topaz.” Amethyst and citrine are both varieties of quartz, one of the most common minerals in the Earth’s crust. The natural abundance and infinite variety of quartz have made it the most widely used of all gem minerals. In its pure form, quartz is colorless and transparent. However the colors of citrine and amethyst are caused by chemical impurities. In the case of citrine, it is iron content that gives it its color. Natural yellow citrine is usually pale yellow and is very rare. Most commercial citrine is made by heat-treating amethyst. In fact, heat treated citrine is sometimes referred to as “burnt amethyst.” Citrine rates a 7 on the hardness scale. Because the stone is heat sensitive, it should be protected from excessive exposure to heat or light.
Your citrine could last forever if you take care of it in the right way. It must be shielded from any type of situation where it could be scratched or hit. That said however, it is pretty good at standing up to your normal everyday wear and tear. It is very important for a citrine not to be left in the sun, or to be in situations, for example sunbathing, where it will be exposed to prolonged sunlight or heat. Because of its sensitivity to heat, the stone’s color could change and fade into a lighter color. You can use any commercial jewelry cleaner or plain soap and warm water (using a soft brush) to wash your citrine. Make sure you rinse and dry it thoroughly after cleaning it. You may also have the stone cleaned in an ultrasonic cleaner, however steam cleaning is not recommended.