Citrine is the transparent, pale yellow to brownish orange variety of quartz. It is rare in nature. In the days before modern gemology, its tawny color caused it to be confused with topaz. Today, its attractive color, plus the durability and affordability it shares with most other quartzes, makes it the top-selling yellow-to-orange gem. In the contemporary market, citrine’s most popular shade is an earthy, deep, brownish or reddish orange.