Gemstone Colors and Transition Metals

What Causes Gemstones to Get Their Color

Gemstones are minerals that can be polished or cut for use as an ornament or jewelry. The color of a gemstone comes from the presence of trace amounts of transition metals. Take a look at the colors of common gemstones and the metals responsible for their color.


Amethyst is purple quartz, a silicate. Jon Zander

Amethyst is a colored form of quartz that gets its purple color from the presence of iron.


Aquamarine is a translucent pale blue or turquoise variety of beryl. Deidre Woollard/Flickr

Aquamarine is a blue variety of the mineral beryl. The pale blue color comes from iron.


Colombian emerald crystals.
Colombian emerald crystals. Productos Digitales Moviles

Emerald is another form of beryl, this time in a green color due to the presence of both iron and titanium.


This is a faceted garnet.
This is a faceted garnet. Wela49, Wikipedia Commons

Garnet gets its deep red color from iron.


Gemstone-quality olivine (chrysolite) is called peridot.
Gemstone-quality olivine (chrysolite) is called peridot. Olivine is one of the most common minerals. It is a magnesium iron silicate with the formula (Mg,Fe)[sub]2[/sub]SiO[sub]4[/sub]. S Kitahashi,

Peridot is the gemstone form of olivine, a mineral formed in volcanoes. The yellow-green color comes from iron.


1.41-carat faceted oval ruby.
1.41-carat faceted oval ruby. Brian Kell

Ruby is the name given to gemstone-quality corundum that is pink to red in color. The color comes from the presence of chromium.


Star Sapphire
This star sapphire cabochon displays six-ray asterism. Lestatdelc, Wikipedia Commons

Corundum is any color besides red is called sapphire. Blue sapphires are colored by iron and titanium.


Spinels are a class of minerals that crystallize in the cubic system. They can be found in a variety of colors. Géry Parent/Flickr

Spinel most often appears as ​a colorless, red or black gem. Any of several elements may contribute to their color.


Turquoise pebble that has been smoothed by tumbling.
Turquoise pebble that has been smoothed by tumbling. Adrian Pingstone

Turquoise is an opaque mineral that gets its blue to green color from copper.