Amethyst, Citrine and Ametrine are found in small to large sizes. Very large sizes in rich, deep colors have always been rare. Darker hues of Amethyst are rarely enhanced to perfect their color, although some varieties do respond well to heat enhancement. Brownish varieties, when heated, magically turn into the bright yellow or orange colors known as Citrine. This enhancement method is permanent, and stable and will last for the life of the stone.
Most quartz gems are inexpensive especially the colorless, rose, and other pale colors.
Citrine may command prices of several dollars per carat. Amethyst of large size and fine color may well cost several tens of dollars per carat.