Ruby facts for kids

Kids Encyclopedia Facts
Ruby
Ruby gem.JPG
A ruby gemstone
General
Category Mineral
Formula
(repeating unit)
aluminium oxide with chromium, Al2O3
Identification
Color Red shades
Luster Vitreous

Ruby is a type of precious stone. It is often associated with emerald, sapphire and topaz. It is usually red, but can sometimes be other colors. It is formed of aluminum and oxygen, Al2O3.

Factors affecting value

Rubies, as with other gemstones, are graded using criteria known as the four Cs, namely color, cut, clarity and carat weight. Rubies are also evaluated on the basis of their geographic origin.

Color: In the evaluation of colored gemstones, color is the most important factor. Color divides into three components: hue, saturation and tone. Hue refers to color as we normally use the term. Transparent gemstones occur in the pure spectral hues of red, orange, yellow, green, blue, violet. In nature, there are rarely pure hues, so when speaking of the hue of a gemstone, we speak of primary and secondary and sometimes tertiary hues. Ruby is defined to be red. All other hues of the gem species corundum are called sapphire. Ruby may exhibit a range of secondary hues, including orange, purple, violet, and pink.

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Ruby Facts for Kids. Kiddle Encyclopedia.