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What marbles glow under black light?

Marbles that glow under black light, also known as ultraviolet (UV) light, can create a stunning display and illuminate your collection. The glow comes from fluorescent and phosphorescent compounds added to the glass or acrylic. When these marbles are exposed to UV light, they absorb the energy and re-emit it as visible light.

Marbles That Glow Under Black Light

There are several types of marbles that will glow brightly under black light:

  • Uranium Glass Marbles – Made with trace amounts of uranium oxide that fluoresce green or yellow.
  • Vaseline Glass Marbles – Contain uranium oxide to fluoresce green and manganese that glows purple.
  • Custard Glass Marbles – Fluoresce yellow due to uranium oxide content.
  • Superman Glass Marbles – Made with uranium oxide and fluoresce yellow-green.
  • Fluorescent Dyed Marbles – Dyed with fluorescent pigments to produce bright colors.
  • Glow in the Dark Marbles – Contain phosphorescent compounds to absorb and re-emit light.
  • Novelty UV Marbles – Crafted specifically to glow under black light.

How Marbles Glow Under Black Light

The glowing effect of marbles under black light is caused by fluorescence and phosphorescence. Here is an explanation of how these work:


Fluorescent substances contain atoms that can absorb ultraviolet radiation and re-emit that energy at a longer wavelength in the visible spectrum. This causes vibrant glowing colors visible to the human eye.

Some examples of fluorescent atoms used in glass and acrylic marbles include:

  • Uranium – Emits bright green/yellow fluorescence.
  • Manganese – Fluoresces purple.
  • Calcium – Glows orange under UV light.
  • Boric acid – Exhibits green fluorescence.

Specialized fluorescent dyes are also added to acrylic and glass marbles to produce vivid colors.


Phosphorescent marbles contain compounds capable of absorbing UV radiation and slowly re-emitting it over time as visible light. The compounds cause the marble to continue glowing after the UV “black” light is turned off.

Phosphors used in glow-in-the-dark marbles include:

  • Strontium aluminate
  • Zinc sulfide
  • Calcium sulfide

The phosphorescent compounds are activated by the UV light and relax slowly, releasing their energy as a visible glow that can persist for minutes to hours after turning off the black light.

History of Uranium Glass Marbles

One of the most brilliant fluorescing marbles under black light is uranium glass. Here is some history behind these glowing marbles:

  • Developed in the early 19th century as uranium was added to glass to imitate more expensive lead crystal.
  • Fluorescence of uranium glass discovered in the 1840s.
  • Uranium glass marbles first created around 1840 by Joseph Locke of New England using slag glass.
  • Mass production of uranium marbles began in the late 1920s. The Lucas Company in the U.S. created popular Superman marbles using uranium-doped glass.
  • Use of uranium declined in the mid-20th century due to concerns over radiation, although uranium glass is considered safe.
  • Uranium marbles are now collectibles that glow brilliantly under black light.

Safety of Uranium Glass Marbles

Although glass marbles containing uranium may sound hazardous, uranium glass is considered safe and the radiation levels are negligible, especially in marble sizes. However, safety precautions should still be used:

  • Avoid placing uranium marbles directly on the skin for extended periods of time. The glass helps shield the low levels of radiation.
  • Wash hands after handling uranium marbles.
  • Do not grind or abrade uranium glass as this can release more concentrated radioactive dust.
  • Limit UV black light exposure time to several minutes at a time to avoid overexposure.

When properly handled, uranium marbles present very minimal radiation risk but provide an eye-catching fluorescence under black light.

Tips for Making Marbles Glow Under Black Light

To make the most of your glowing marble collection under UV light, follow these tips:

  • Use a powerful black light bulb in the 365-385 nm wavelength range.
  • Choose a room that can be made completely dark to allow the fluorescent glow to be visible.
  • Display the marbles against a black background that won’t impede the glow.
  • Organize the marbles by fluorescence color for a stunning rainbow effect.
  • Rotate the marbles under the black light to activate all sides.
  • Photograph the marbles while they glow for lasting images.

Most Brilliant UV Glowing Marbles

While many marbles exhibit some fluorescence under black light, these varieties are known for their exceptionally vibrant glow:

Marble Type Fluorescence Color
Vaseline Glass Green/Purple
Superman Bright Yellow-Green
Neon UV Reactive Vivid Neon Rainbow

The strong radioactivity of uranium produces brilliant fluorescence in vaseline and superman marbles. Novelty UV marbles designed specifically for black light effects can glow with stunning neon rainbow colors.

Glowing Marble Photography Tips

Photographing glowing marbles requires some special techniques. Follow these tips for great UV marble photos:

  • Use a DSLR camera capable of long exposure shots.
  • Mount the camera on a tripod to keep it still for long exposures.
  • Use manual mode to control exposure settings.
  • Select a low ISO, around 100-400.
  • Opt for a wide aperture, f/2.8 or wider if possible.
  • Use exposures of 5-30 seconds to capture the glow.
  • Edit photos to boost vibrance and contrast.

Experiment with exposures to achieve an appealing balance of black background and glowing marble colors. Post-processing can enhance the otherworldly effects.


Under the influence of UV black light, certain special marbles burst into an entrancing visible glow through unique fluorescent and phosphorescent properties. Uranium glass marbles produce brilliant green/yellow fluorescence. Novelty UV marbles fluoresce intensely in neon shades. With the right lighting and photography, these glowing marbles can create a magical experience and take marble collecting to the next level.

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