Composition: Aluminum oxide
Nomenclature: Named after the Latin word rubeus which means "red" because of its color.
Industrial Uses: Gemstones, precision bearings, abrasives.
Additional Notes: Ruby is the red, gem variety of corundum. A member of the Hematite group of minerals. Generally regarded as the second most precious of the precious gemstones (emerald is first; diamond is third).
Afghanistan : Scott 1300 : 40 afghani : 5 Dec 1988
Ruby (corundum)
Burma/Myanmar : Scott 306 : 50 pyas : 26 Jan 1991
Ruby (corundum)
Comoro Islands : Scott 930a : 375 francs : 1998
Ruby (corundum)
Kenya : Scott 111 : 20 shillings : 13 Dec 1977
Ruby (corundum)
Sri Lanka : Scott 510 : 5 rupees : 16 Jun 1976
Ruby (corundum)
Thailand : Scott 624 : 75 stang : 7 Jun 1972
Ruby (corundum); quartz
Tanzania : Scott 314 : 30 shilling : 22 May 1986
Ruby (corundum)