The yellow topaz and citrine are often confused, and even misidentified by amateur gem enthusiasts. Although these two gemstones share the coveted spot as November’s birthstone, they are different gems. Each gemstone has different origins that derive from a completely different crystal system, where they inherit different molecular, optical and physical properties. Yellow citrine is a quartz crystal that is formed out of silicon dioxide. Topaz is a fluoro-silicate of aluminum.
Their refractive index is also different. This means the light bends differently as it passes through a quartz then when it passes through a topaz. Unlike other gemstones, topaz does not always derive its natural colour from impurities in the crystal but rather from a gap or an extra electron in the crystal structure. Most topaz is mined white, but it can be mined in shades of natural yellow, light grey, blue, orange, brown, green or pink. While a topaz with naturally occurring colour is more rare and duly prized, most citrine on the market is heat treated to achieve the yellow hues. Naturally occurring yellow citrine is very rare. So rare that there are no tools or technology to even distinguish between a heated treated citrine and a naturally mined yellow. The original hue of an amethyst quartz actually determines the yellow colour of the citrine. Similar to amethyst, citrine quartz is 7 on Moh’s Hardness Scale (hard enough to scratch window glass) while Topaz is 8 (slightly harder). The molecular structures of the citrine and topaz inherit colour, hardness, and light differently. Each gemstone is not only a completely different mineral, but they are also valued very differently.