What is Ruby?
{{otheruses}} {{Infobox mineral | name = Ruby | category = [[Corundum]] variety, [[Oxide mineral]] | boxwidth = | boxbgcolor = pink | image = Ruby gem.JPG | imagesize = | caption = A ruby gemstone | symmetry = | unit cell = | formula = [[aluminium oxide]] with [[chromium]], Al<sub>2</sub>O<sub>3</sub> | molweight = | color = Red shades | habit = | system = | twinning = | cleavage = | fracture = | tenacity = | mohs = | luster = [[Lustre (mineralogy)|Vitreous]] | polish = | opticalprop = | refractive = | birefringence = | dispersion = | pleochroism = | fluorescence= | absorption = | streak = | gravity = | density = | melt = | fusibility = | diagnostic = | solubility = | diaphaneity = | other = | references = <ref name=Mindat>{{cite web|url=http://www.mindat.org/min-3473.html |title=Ruby at Mindat |publisher=Mindat.org |accessdate=23 August 2013}}</ref> }} A '''ruby''' is a kind of precious stone. It is often associated with [[emerald]], [[sapphire]] and [[topaz]].<ref name=Mindat/> It is usually red, but can sometimes be other colors.<ref name=Mindat/> It is formed of [[aluminum]] and [[oxygen]] (Al<sub>2</sub>O<sub>3</sub>),<ref name=Mindat/> and that means it's a kind of [[corundum]]. A small amount of [[chromium]] makes the color. They are the most popular red gemstone, and is aften linked with the birthmonth of July. [[File:Ruby - Winza, Tanzania.jpg|thumb|Natural rubies]] ==References== {{reflist}} {{sci-stub}} [[Category:Gemstones]] [[Category:Birthstones]]