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Throw some shade.

Crystals That, Fade in the Sun

Color centersUV and heatKeep shaded

Crystals that fade in the sun include amethyst, smoky quartz, rose quartz, fluorite, kunzite and celestite. Most of them owe their color to tiny defects made by natural radiation, and light and heat slowly undo those defects, so a sunny windowsill is the worst place to keep them.

Why crystals fade in the sun

Crystals fade in the sun because many crystal colors come from color centers: spots in the atomic structure where natural radiation knocked an electron out of place. Those damaged spots absorb certain colors of light, and the rest is the color you see. Ultraviolet light and heat supply enough energy to repair the damage, and the color drains away a little at a time. A few stones fade for other reasons, such as dye or a slow chemical change that light speeds up.

Crystals that fade in the sun

Crystals that fade in the sun are worth knowing by name if you display stones near windows. Here are the common ones and the reason for each.

  • Amethyst: iron plus natural radiation. Long sun leaves it paler, and strong heat can turn it yellow.
  • Pink amethyst: a pale color to start with, so even a little fading shows. Keep it shaded.
  • Super seven: its amethyst and smoky quartz zones are both radiation colors.
  • Smoky quartz: aluminum plus natural radiation. Sun and heat lighten the smoke.
  • Citrine: natural citrine colored by radiation can pale, while heat-treated citrine, the common kind, has already been cooked and holds steady.
  • Rose quartz: colored by microscopic pink fibers, and known to pale after long exposure to strong light.
  • Fluorite: purple, blue and green fluorite from some localities fades noticeably in daylight.
  • Kunzite: pink to violet spodumene whose color fades in strong light, which earned it the nickname evening stone (GIA on kunzite).
  • Celestite: its pale sky blue comes from a color center, and sun bleaches it.
  • Larimar: its blue pales with long exposure to strong light and heat.

Rose quartz fade

Rose quartz fade is gradual: the pink, which comes from microscopic fibers of a mineral related to dumortierite, pales with long exposure to strong light and heat. A sphere kept on a sunny sill can end up visibly lighter than a twin kept in a cabinet. Keep rose quartz towers and spheres out of direct sun and display them on a shaded shelf. GIA's rose quartz description has more on the stone.

How long it takes crystals to fade

How long it takes crystals to fade depends on the mineral, the locality and how much direct sun they get, so there is no single number. Some kunzite and fluorite lose color quickly in strong light, while amethyst and rose quartz usually change slowly. Heat speeds everything up, so a hot windowsill or a car dashboard is worse than a cool, bright room.

Sun safe crystals

Sun safe crystals get their color from stable chemistry, such as iron oxide or chromium, or have little color to lose. One caution applies to all of them: a clear sphere in a window works like a magnifying glass and can scorch whatever sits at its focus.

  • Clear quartz and milky quartz.
  • Agate, jasper, carnelian and tiger's eye, colored by iron oxides.
  • Black tourmaline and obsidian.
  • Garnet and hematite.
  • Pyrite, which is sun safe but should stay dry.
  • Green aventurine and ruby in fuchsite, colored by chromium-bearing mica.

How to display crystals that fade

To display crystals that fade, pick a spot with indirect light and no direct sun at any hour of the day. LED lighting gives off very little ultraviolet and less heat than halogen bulbs, so it is gentler on color than halogen or daylight. Rotate pieces out of bright rooms now and then, and keep the most sensitive ones, like kunzite and celestite, in a closed cabinet.

Other stones that change in sunlight

Other stones that change in sunlight do it for reasons besides color centers.

  • Sherry brown topaz from some deposits, such as Topaz Mountain in Utah, fades to colorless in sunlight.
  • Amber slowly darkens and can develop fine surface cracks as light and air oxidize it.
  • Dyed agate, dyed howlite and other dyed stones lose their dye, often unevenly.
  • Opal can crack from the heat of a sunny window as it dries out.

Crystals That Fade in the Sun FAQ

Will amethyst fade in sunlight?

Amethyst will fade in sunlight with months of direct exposure, and heat speeds it up, so keep it away from sunny windows.

Can citrine fade in the sun?

Citrine can fade in the sun if its color is natural and radiation-made, while most commercial citrine is heat-treated amethyst that holds its color well.

What crystals cannot be left in the sun?

Crystals that cannot be left in the sun include amethyst, pink amethyst, smoky quartz, natural citrine, rose quartz, fluorite, kunzite and celestite.

Which crystals can be in the sun?

Crystals that can be in the sun include clear quartz, agate, jasper, black tourmaline, obsidian, garnet, hematite and pyrite.

Does sunlight charge crystals?

Sunlight does not charge crystals in any measurable way. Charging stones in the sun is crystal lore, and for amethyst or rose quartz it is a slow way to fade them.

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