Lowsilica

Lowsilica is a descriptive term used across disciplines to denote substances or compositions that contain silica (SiO2) at levels lower than a reference standard. The concept is used to compare materials within a context where silica content strongly influences properties such as viscosity, durability, and crystallization behavior.

In geology and volcanology, low-silica magmas typically yield basaltic to andesitic compositions. These magmas generally produce less viscous melts, which can flow more readily and erupt effusively rather than explosively. Silica content also affects crystallization pathways, gas retention, and the style of volcanic activity. Plate tectonic setting often correlates with silica levels: divergent boundaries and some intraplate settings commonly host lower-silica magmas, while subduction zones are associated with higher-silica magmas.

In glassmaking and ceramics, lowsilica formulations reduce the silicate-network connectivity of the melt. Lower silica content can enable lower melting temperatures and different processing characteristics when combined with fluxes or other oxides. Such compositions can alter viscosity, working temperatures, thermal expansion, and chemical durability, making them useful for specialized glass products, foams, or certain ceramic systems.

Thresholds for what counts as lowsilica are not universal and vary by field, measurement method, and standard reference material. The term serves as a relative descriptor rather than a fixed composition, highlighting how silica content influences physical behavior and processing in geological and industrial contexts.

See also: silica, silicate, basalt, glass, petrology.