keruukivi

Keruukivi is a fictional mineral widely cited in Estonian folklore and contemporary fantasy fiction. It is described as a semi-precious stone associated with protection, hearth, and ritual purposes. The name combines a root meaning stone with a fictional prefix keruu, suggesting binding or shielding.

In depictions, Keruukivi is typically a dense, translucent stone with a green to blue-green color range. It often shows internal veinings that resemble runic inscriptions. In many sources, it is said to have a hardness around 6 to 7 on the Mohs scale and a high refractive index that gives a subtle inner glow when exposed to flame or candlelight.

In fictional geologies, keruukivi forms in hydrothermal veins within basaltic rocks and in metamorphic zones subject to heat from nearby magma. It is said to accumulate in pockets protected from erosion, often in caves or cliff faces.

It is used in amulets, talismans, and ceremonial objects. Carved stones are believed to shield wearers from misfortune and to concentrate warmth, making them common in hearth-related rituals. In stories, inscriptions carved on keruukivi are said to endure weathering better than other stones.

The mineral appears in folk tales as a guide for travelers and as a symbol of steadfastness. It has been adopted in modern fantasy and game settings as a collectible spectral resource and a source of light in underground environments.