Crystal and Gemstone Materials

Crystal materials turn an object into a gemstone. Each one is a see-through or semi-see-through surface that bends the light passing through it, tints it with the stone's colour, and reflects its surroundings strongly from a polished top layer. Put a crystal on a shape, a 3D model or a line of 3D text and it reads as a cut stone, a mineral or a precious object. The family has twelve stones, each tuned to its real-world colour and to how much it bends light.

What is in the family

• Clear and brilliant: Diamond bends light the most and reflects the most; Quartz is a clear, slightly softer crystal.
• Deep precious colours: Ruby is a deep pinkish red, Sapphire a rich royal blue, Emerald a saturated green. They let less light through than the lighter coloured stones, so their colour reads as dense.
• Lighter coloured stones: Amethyst (violet), Topaz (warm peach-gold), Citrine (sunny yellow) and Aquamarine (bright mint-aqua) are clearer and brighter.
• Milky and opaque: Opal is pale and cloudy with very strong reflections, Jade is a soft, semi-opaque green, and BlackOnyx is almost solid black with a glossy surface.

How the settings change the look

All stones share the same controls:

• Transmission is how much light goes through. Diamond is fully clear at 1; Ruby sits at 0.7, Jade at 0.5, BlackOnyx at 0.3. Lower values make the colour solid and the stone look denser.
• IOR is how strongly light bends inside the stone. It runs from 1.45 for Opal to 2.42 for Diamond; higher values break the background into more distorted, sparkling pieces.
• Env Map Intensity is the strength of the reflections. Crystals sit higher than ordinary glass, from 1 for onyx up to 2.5 for diamond, which is where their brilliance comes from.
• Roughness blurs what you see through the stone and softens its highlights. The precious stones are near 0; Opal and Jade are rougher, which makes them cloudy.
• Thickness is how deep the stone behaves, Clearcoat and Clearcoat Roughness add the polished outer layer, and Color sets the stone's tint.

How to choose

Pick the stone by colour first, then check how see-through it should be. For sparkle, choose a high IOR and high reflections: Diamond, then Sapphire and Ruby. For a calm, soft look, choose Jade, Opal or Quartz. For dark, dramatic objects, use BlackOnyx.

The material does not cut the stone for you: the facets come from the object's geometry. Faceted or low-poly shapes show off refraction and highlights far better than a smooth sphere. Gems also need light and surroundings: place them in front of colour or other objects, under bright lights or with an environment that has contrast. For softer, everyday versions of clear and coloured glass, see the glass materials.