Remainsstone

Remainsstone is a term used in speculative fiction and worldbuilding to denote a class of minerals that encase and preserve organic remains within their crystalline matrix. In most portrayals, remainsstone forms when fine mineral precipitates surround a once-living organism, capturing its morphology as a fossil inside the rock. The term combines remains and stone to emphasize its preservation function.

Physical properties: Remainsstones are typically composed of silica or calcite with traces of phyllosilicates; hardness 5–7 on Mohs; color ranges from pale gray to emerald green, often with opalescent or iridescent overtones; some varieties exhibit fluorescence under ultraviolet light; micro-impressions of bones, leaves, or soft-tissue structures may be visible under magnification.

Formation and distribution: In fictional settings, remainsstone forms in sedimentary basins with prolonged low-oxygen conditions where organic material is rapidly mineralized. It is described as occurring in only select regions, such as the Glimmer Basin and the Isthmus of Shale in worldbuilding texts. In-universe, discoveries are rare and often associated with ancient flood events.

Uses and cultural context: Museums display remainsstones as showpieces of fossil preservation; jewelers cut them into cabochons; in some legends they are believed to store memories or ancestral knowledge. Researchers in the fiction may study their structure to infer paleoecology or to date the specimen. Ethical and conservation concerns arise over extraction and trade.

Notable examples: The Echo Stone, The Weaver's Remnant.