A gem is sometimes so brilliant that it appears to not merely refract the available light, but to add
to the light — possibly to an altogether ridiculous degree, if Played for Laughs
Subtrope of Fantastic Light Source
. Can sometimes overlap with Power Crystal
via Power Glows
Folklore and Mythology
- In the Russian Mythology and Tales, specifically the byliny, large gems are commonly attributed with the ability to emit light and are used in that capacity by the bogatyrs to light the way.
- In medieval folklore, it was held that an absolutely perfect ruby would glow from within, like a red-hot coal.
- In The Adventure of the Blue Carbuncle, the titular gemstone is described as "a brilliantly scintillating blue stone, rather smaller than a bean in size, but of such purity and radiance that it twinkled like an electric point".
- In The Silmarillion, the three Silmaril gems were made from the light of magic trees, causing the gems to glow perpetually. The light is so pure that the gems burn any evil being that touches them. One of the gems was eventually made into a star.
- In The Hobbit the Arkenstone of Thrain (AKA The Heart of the Mountain) is described as shining with its own inner light.
- The eponymous stormlight in The Stormlight Archive is energy that suffuses any gem exposed to one of the powerful storms that frequently ravage the setting. The glowing gems are thus commonly used as a light source, and the light can also be drawn in by magic-users or power magitek.
- Glowing gems are visible signs of Deryni power:
- The gryphon-shaped emerald inlay of Morgan's signet ring glows against the black onyx background when the ring is magically attuned to the Deryni mage holding it. Properly attuned to Duncan in Deryni Rising, it allows him to unlock a secret compartment in the high altar of Saint Hilary's Basilica in Rhemuth.
- The gems used in the Haldanes' power triggering ritual glow internally when a drop of blood from the next heir(s) comes in contact with the stones. This is true for both the Eye of Rom (a single red ruby mounted as an earring) and the Ring Of Fire (a ring with red garnets set in a cluster).
- Shiral crystals also glow when a Deryni or someone with a triggerable potential concentrates sufficiently.
- In the Tales of Kolmar trilogy, dragons' soulgems gleam with an inner light when they are alive. When dead, the gem shrinks and becomes dull, but it will glow again during a Kin-Summoning. The soulgems of the Lost - the dragons who were cursed to lose their sentience - still glow, unattached to the dragon, thousands of years later, so the others know that the Lost are still "alive" somewhere out there.
- In Magic: The Gathering the art for Prophetic Prism (see also the page image) and Chromatic Star depicts these artifact gems as this. It's Justified in that they are Mana altering artifacts, capable of energy into death, holy or elemental Mana.
- Dungeons & Dragons
- The following magical gems in 1st/2nd Edition glowed either on command or continuously: Gem of Brightness, Gem of Delusion, Jewel of Obsession, the Jacinth of Inestimable Beauty, and the huge glowing orange Cursed Wishing gem in S1 Tomb of Horrors.
- A number of 1st Edition adventures included gems with a Continual Light spell cast upon them to make them glow, such as T1-4 The Temple of Elemental Evil and I12 Egg of the Phoenix. Continual Light creates a white light: if the gem is colored, the light it gives off will be the same color as the gem.
- Module I5 Lost Tomb of Martek. When one of the Star Gems is placed in the hollow below the writings on the Obelisk Stone, the Gem starts to glow with a soft white light. When it's pointed in the direction of Martek's tomb it will flare up with a brilliant white light.
- Clerics of the gnome deity Segojan Earthcaller cast Light or Continual Light spells on large, well-cut gems for use as holy symbols, causing them to glow from within.
- Call of Cthulhu
- Dreamlands campaign setting, adventure "Pickman's Student". While exploring the dream version of Elder Yuggoth, the PCs can encounter 4 dully glowing green gems that some Mi-go are using to restrain a Dark Young of Shub-Niggurath. Later on the PCs see one of the Mi-go sacrifice the Dark Young with a knife that has a blade made of the glowing gemstone.
- Campaign Spawn of Azathoth. The Investigators can acquire two stones that are necessary to deal with the Seed of Azathoth. At the climax of the adventure, the stones become strange fist-sized, glowing ovoid gems that increase greatly in weight.
- Earthdawn. During the Scourge, light spells were cast on quartz crystals, which were then used to brighten underground kaers and sealed cities. After the Scourge, as the population of Barsaive re-entered the outside world, light quartz continued to be used to dispel the darkness.
- Traveller. MegaTraveller Journal magazine #3, article "Races of the Domain: Crenduthaar". Chagas gems are a crystallized mineral salt found on the planet Thaar that can be as large as a human fist. They are blood-red, translucent and contain a pulsing inner light.
- In Colossal Cave, the Plover Room is filled with an eerie green light — which, apparently, comes from the enormous emerald in the middle.
- In one Tom and Jerry cartoon, Tom's would-be girlfriend has her rich boyfriend buy for her a huge diamond (about a metre across) — which can only be safely looked at through welding goggles.
- In Disney's Aladdin, the giant red gemstone in the lamp chamber of the Cave of Wonders illuminates its altar without any other apparent source of light. This could simply be magic of some kind, considering the nature of the cave.
- In Avatar: The Last Airbender there is the Underground City of Old Ba Sing Se, which has been buried underneath the modern one. It's constantly lit by green crystal used as street lamps.
- In the Popeye animation "Popeye In Aladdin And His Wonderful Lamp", Aladdin (played by Popeye) asks the genie of the lamp to deliver a chest of gold and jewels to the princess (played by Olive Oyl). The contents include several head-sized gemstones that bathe the room in colored light, including a diamond that is so brilliant the princess needs sunglasses to look at it — and her window turns it into a spotlight to illuminate Aladdin posing outside on his horse.
- Some diamonds are fluorescent. This will cause them to shine with more (visible) light than is shed on them.
- As the acronym indicatesnote , lasers increase the amount of light effectively available by making the photons work with, rather than against, each other. The first laser was a(n artificial) ruby.