Top 10 Gemstones with Two or More Colors Occurring in One Single CrystalMetal_Treasure Very often one single crystal is zoned and the crystal has at least 2 color zones with different colors. Not all gems have multicolored crystals - some gems occur in many colors but never in one crystal so you can't get a ring with two or more colors.
The Top Ten
Sapphire stones that exhibit two or more colors within a single stone are know as "parti colored" sapphires. They cannot be created synthetically and only occur naturally. Australia is the largest source of particolored sapphire. - Metal_Treasure
Often two or more colors are found in a single tourmaline crystal and they are commonly known as bi-color tourmaline.
Bi-color tourmaline gemstones occur in many color combinations and show multiple color zones throughout the crystal. Bi-color tourmalines are highly prized when the color zoning is well defined and the colors are vivid.
An example is the Watermelon Tourmaline where you have green and red zones in one crystal. - Metal_Treasure
Sapphire can be any color except red, and Star Sapphire is with a white star - Metal_Treasure
A rare natural combination of amethyst and citrine, purple and yellow in one crystal. - Metal_Treasure
A Tanzanite crystal often has 3 zones - blue, purple/violet and red - Metal_Treasure
Red with a white star - Metal_Treasure
This gem looks really cool - AliciaMae
Yellow-ish with a white strip - Metal_Treasure
The golden needles you see can also be silver, copper red or deep black. - Metal_Treasure
It's my fave gemstone well... Was, now mines is Painite. - X_the_Unown