Substantiiveina

Substantiiveina is a fictional mineral species created for world-building and speculative geology. It is described as a silicate-rich mineral that forms in high-temperature hydrothermal veins of an imagined continent called Aeloria. The mineral is typically blue-green, with a glassy to vitreous luster, and it crystallizes in elongated prismatic crystals, often occurring in aggregates rather than solitary prisms.

Substantiiveina commonly contains iron and magnesium as major constituents, with smaller amounts of titanium and aluminum. It has a Mohs hardness near 6 and exhibits distinctive optical properties, including moderate pleochroism from blue to emerald-green under polarized light in in-world microscopy.

In its geological context, Substantiiveina is described as being associated with copper minerals and quartz veins. Its stability range is stated to be high-temperature, and heating above certain thresholds is said to alter the color to a dull brown, a feature used in lore to explain weathering of ruins.

The name Substantiiveina is a portmanteau inspired by Latin substantiva (substantive) and the common mineral suffix -ina. In fiction, the mineral is used as a symbol of endurance and substance, and is depicted in artifacts and jewelry across several cultures. Some fictional scholars claim its isotopes could power ancient engines, though no real-world mineral corresponds to Substantiiveina.