Editing Sapphire (section)

===Blue sapphire===
{{redirect|Blue Sapphire|the cruise ship|Blue Sapphire (ship)|the horse race|Blue Sapphire Stakes}}
[[File:Geschliffener blauer Saphir.jpg|thumb|upright|Teardrop-shaped blue sapphire]]

Gemstone color can be described in terms of [[hue]], [[Colorfulness|saturation]], and [[Lightness (color)|tone]]. Hue is commonly understood as the "[[color]]" of the gemstone. Saturation refers to the vividness or brightness of the hue, and tone is the lightness to darkness of the hue.<ref name="Hughes-2017"/>{{rp| 333–401}} Blue sapphire exists in various mixtures of its primary (blue) and secondary hues, various tonal levels (shades) and at various levels of saturation (vividness).

Blue sapphires are evaluated based upon the purity of their blue hue. [[Violet (color)|Violet]] and [[green]] are the most common secondary hues found in blue sapphires.<ref name="Hughes-2017"/>{{rp|333–401}} The highest prices are paid for gems that are pure blue and of vivid saturation. Gems that are of lower saturation, or are too dark or too light in tone are of less value. However, color preferences are a personal taste.<ref name="Hughes-2017"/>{{rp| 333–401}}

The {{convert|423|carat|adj=on}} [[Logan sapphire]] in the [[National Museum of Natural History]], in [[Washington, D.C.]], is one of the largest [[facet]]ed gem-quality blue sapphires in existence.[[File:Sapphire III cropped flash.jpg|thumb|left|Dark blue sapphire, probably of Australian origin, showing the brilliant surface luster typical of faceted corundum gemstones]]