Editing Ruby (section)

=== Color ===
[[File:Rubin (Corundum) - Hunza Valley, div. Gilgit, Northern Areas, Pakistan.jpg|thumb|Ruby (Corundum) - Hunza Valley, div. Gilgit, Northern Areas, Pakistan.]]
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.<ref name="wise">{{cite book|author=Wise, Richard W. |title=Secrets Of The Gem Trade, The Connoisseur's Guide To Precious Gemstones |pages=18–22 |isbn=0-9728223-8-0 |year=2006|publisher=Brunswick House Press}}</ref> 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.

<gallery mode="packed" heights="160">
Image:Ruby cristal.jpg|A naturally occurring ruby crystal
Image:Ruby gem.JPG|Natural ruby with inclusions
Image:Cut Ruby.jpg|A cut pink ruby
Image:Rubis, calcite 14.jpg|Purple rubies
</gallery>