corundum
Sapphire's base material
Corundum is an extremely hard mineral, second only to diamond.
In its pure form it's colorite, but trace impurities create gemstones: chromium produces red corundum (ruby), while iron and titanium yield blue (sapphire).
Industrial-grade corundum serves as an abrasive for grinding and polishing.
Precious red gemstone
- sapphireBlue precious corundum
- cornflower-blueLight purplish-azure hue
- KashmirContested Himalayan region
- CeylonSri Lanka's former name
Burmese · Thai · Montana · Australian · synthetic · natural · untreated
Granular polishing mineral
- sandpaperAbrasive-coated finishing material
- grindingMolar action sometimes
- polishingSmoothing by friction
- lappingFine abrasive finishing process
grit · buffing · sanding · finishing · sharpening · scouring · blasting · deburring
Six-edged polygon's form
- trigonalThree-angled in form
- latticeOpenwork of crossed strips
- prismaticLight-dispersing, multicolored
- anisotropicVarying with orientation
twinning · asterism · symmetry · facet · cleavage · morphology
Domed, unfaceted gemstone
- facetedHaving multiple flat surfaces
- carat200 milligrams exactly
- clarityState of being understandable
- cutSeverance or reduction
brilliance · luster · setting · pendant · earring · tiara · heirloom · birthstone
Oxide of a light metal
- metamorphicUndergoing structural change
- igneousFormed from cooled magma
- marbleRecrystallized limestone rock
- schistPlaty-mineral metamorphic rock
Impervious to abrasion
- durabilityResistance to wear
- toughnessResilient durability under strain
- adamantineUtterly impervious, unshakeable
- wear-resistantAble to withstand friction
dense · rigidity · hardened · abrasion-resistant · industrial-grade · resilience · strength · solidity
Oxide mineral, octahedral crystals
- topazSemiprecious aluminum silicate crystal
- garnetRed semiprecious stone
- zirconZirconium silicate crystal
- tourmalineBoron silicate gemstone family
Posture or orientation
- semiconductorPartial electrical conductor
- refractoryResistant to heat/control
- ceramicFired clay material
- high-temperatureVery great heat
ruby
Precious red gemstone
- sapphireBlue precious corundum
- cornflower-blueLight purplish-azure hue
- KashmirContested Himalayan region
Ceylon · Burmese · Thai · Montana · Australian · synthetic · natural · untreated
emery
Granular polishing mineral
- sandpaperAbrasive-coated finishing material
- grindingMolar action sometimes
- polishingSmoothing by friction
lapping · grit · buffing · sanding · finishing · sharpening · scouring · blasting · deburring · smoothing
hexagonal
Six-edged polygon's form
- trigonalThree-angled in form
- latticeOpenwork of crossed strips
- prismaticLight-dispersing, multicolored
anisotropic · twinning · asterism · symmetry · facet · cleavage · morphology
cabochon
Domed, unfaceted gemstone
cut · brilliance · luster · setting · pendant · earring · tiara · heirloom · birthstone · precious
alumina
Oxide of a light metal
- metamorphicUndergoing structural change
- igneousFormed from cooled magma
- marbleRecrystallized limestone rock
schist · bauxite · placer · alluvial · xenolith · granite · gneiss
scratch-resistant
Impervious to abrasion
- durabilityResistance to wear
- toughnessResilient durability under strain
- adamantineUtterly impervious, unshakeable
wear-resistant · dense · rigidity · hardened · abrasion-resistant · industrial-grade · resilience · strength · solidity
spinel
Oxide mineral, octahedral crystals
- topazSemiprecious aluminum silicate crystal
- garnetRed semiprecious stone
- zirconZirconium silicate crystal
tourmaline · beryl · diamond · quartz · feldspar · magnetite · hematite
bearing
Posture or orientation
- semiconductorPartial electrical conductor
- refractoryResistant to heat/control
- ceramicFired clay material
- mineralsquartz, marble, granite, limestone, sandstone
- crystalsquartz, amethyst, diamond, citrine, rose quartz
- durable materialstitanium, stainless steel, tungsten, diamond, carbon fiber
- gemologydiamond, ruby, sapphire, emerald, opal
- hard materialsdiamond, tungsten carbide, synthetic diamond, steel, titanium
- aluminaalumina