Corundum

Sapphire

Sapphire is corundum in any colour but red. Blue is the classic, but yellow, pink and green sapphires share the same hardness and optics, which makes them a durable alternative to softer coloured stones.

  • SapphireSapphire
  • Natural sapphireNatural sapphire
  • Yellow sapphireYellow sapphire
  • Natural yellow sapphireNatural yellow sapphire
  • Pink sapphirePink sapphire
  • Green sapphireGreen sapphire

At a glance

Mineral
Corundum (aluminium oxide); blue from iron and titanium
Refractive index
1.77
Dispersion (C–F)
0.011
Specific gravity
4.00
Mohs hardness
9
Wear
Hard enough for rings worn every day.

Sapphire in Jart

The 6 looks in the studio's material library, with the values the renderer uses.

Optics of Sapphire in Jart
StoneColourRIDispersion C–FAbbeSGColour depth
Sapphire#234fde1.770.011694.003.9 mm
Natural sapphire#2f5ad81.770.011694.005 mm
Yellow sapphire#ffc22e1.770.011694.005 mm
Natural yellow sapphire#ffc22e1.770.011694.006 mm
Pink sapphire#f2559a1.770.011694.005 mm
Green sapphire#3aa8841.770.011694.008 mm

RI refractive index (nd). Dispersion C–F nF − nC, the spread between blue and red light; many gem tables quote the B–G figure instead (diamond 0.044, here 0.025). Abbe number: lower means more fire. SG specific gravity, used for carat estimates in Design Facts. Colour depth the path through the stone after which white light takes the stone's full colour; shorter paths look paler.

How it renders

With a refractive index of 1.77, a polished sapphire facet reflects 7.7% of light that meets it face-on (diamond: 17.2%). Light inside the stone that meets a facet more than 34.4° from straight on cannot leave and is reflected back in; the smaller that angle, the more light a good cut returns to the eye (diamond 24.4°, quartz 40.4°).

Its dispersion (C–F) is 0.011, 45% of diamond's, which sets how much fire, the flashes of colour, a render shows under small, bright lights.

All sapphire presets share corundum's optics. The natural presets add clouds and fine inclusions inside the stone; the clean ones look like the best of the trade.

  • 1 mm
  • 3 mm
  • 6 mm
  • 10 mm
Sapphire: the colour of white light after 1, 3, 6 and 10 mm of stone. It takes the full preset colour at 3.9 mm.
  • 1 mm
  • 3 mm
  • 6 mm
  • 10 mm
Natural sapphire: the colour of white light after 1, 3, 6 and 10 mm of stone. It takes the full preset colour at 5 mm.
  • 1 mm
  • 3 mm
  • 6 mm
  • 10 mm
Yellow sapphire: the colour of white light after 1, 3, 6 and 10 mm of stone. It takes the full preset colour at 5 mm.
  • 1 mm
  • 3 mm
  • 6 mm
  • 10 mm
Natural yellow sapphire: the colour of white light after 1, 3, 6 and 10 mm of stone. It takes the full preset colour at 6 mm.

All gemstones · Metals · Sapphire in white gold · Finishes

Render sapphire on your own design.

Open a 3DM, STL or GLB file, or a sample ring, choose the stone and the metal, and render it photoreal in your browser. No account needed.

Try Jart free