Citrine, yellow to red-orange quartz, its sheer abundance being responsible for this "no respect" treatment. That has begun to turn around somewhat in the last couple of decades as fashions have repeatedly emphasized earth tones.
Actually, very little of the quartz which is mined is citrine. Natural stones tend to be pale yellow, often with smoky tones. The vast majority of citrine which is marketed is produced by heating smoky quartz, (which produces light to medium yellows,) and amethyst, (which produces stronger yellows and orange-red to orangey brown shades.) The treatment is usually done right at the mine, and is stable, and fully accepted within the gem trade. Recently, colorless quartz from some mines have been irradiated and heated to produce a neon, slightly greenish yellow, usually called Lemon Quartz.
In the past, it was commonplace for citrine to be given misnomers such as, "Brazilian topaz", "Madeira topaz," etc. The higher gemological knowledge level of both jewelers and the public make this practice rare today. This gem is a fine jewelry stone, with no cleavage and a hardness of 7. Furthermore, its availability in large sizes enables cutters to use it for dramatic and intricate custom cuts. It is also used for gem carvings. Stable in light and not very sensitive to chemicals, this stone requires no special care and can be used for any jewelry application. Virtually all citrine comes from Brazil.