Rubylike gem

• Crystalline gemstone
• Reddish mineral
• Ruby variety
• Gemstone often passed off as a ruby
• Mineral used as a gem
• Ornamental stone
• Occurs in various colors that are used as gemstones
• Ruby ___ (gem)

Wiktionary Word definitions in Wiktionary
n. (context mineralogy English) Any of several hard minerals of cubic symmetry that are mixed oxides of magnesium and aluminium and are used as gemstones of various colours.

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Spinel \Spi*nel"\, Spinelle \Spi*nelle"\, n. [F. spinelle, or LL. spinellus, perhaps from L. spina a thorn, a prickle, in allusion to its pointed crystals.] (Min.) A mineral occuring in octahedrons of great hardness and various colors, as red, green, blue, ...