Eldunar

Eldunar is a fictional mineral described in contemporary fantasy and science fiction as a rare silicate crystal with a characteristic luminescent glow. In most depictions, it forms in hydrothermal vein systems within ultramafic host rocks and is valued for optical stability and distinctive iridescence.

The term eldunar is said to derive from an ancient word meaning heart, reflecting its perceived central role in vein networks in some imagined cultures.

Eldunar crystals occur in quartz-rich veinlets and magnetite seams. Formation is attributed to high-temperature hydrothermal processes and long residence times, with trace elements such as chromium, ytterbium, and manganese contributing to color and luminescence.

Hardness is given as about 6.5 on the Mohs scale; the mineral has a refractive index near 1.75 and shows photoluminescence under ultraviolet light. Its approximate chemical composition is a silicon-aluminum silicate with trace rare earth elements. Crystals are typically prismatic and display iridescent interference colors.

In fictional settings, eldunar is used in high-precision optics, resonators, and jewelry. Its rarity and extraction difficulty drive significant value, and stories describe controlled mining operations, environmental concerns, and ethical debates over access to the resource. Synthetic production is sometimes portrayed but remains expensive.

See also: List of fictitious minerals; iridescent minerals; hydrothermal ore deposits.