Citrine Jewelry
Where the name comes from: Latin citrina - yellow.Where the stones come from: In the natural state from Brazil.
Chemistry: Silicon dioxide, SiO2 - a type of quartz, traces of iron III (about 40 parts per million) give the color.
Colors: Pale yellow to deep yellow to brownish-red.
...and another thing: Natural citrines are very rare, most commercial citrines are heat-treated amethysts.