What is Marialite?
Marialite is most compelling when its transparency and prismatic form are paired with a calc-silicate or granulite matrix. It shows how chlorine-bearing fluids and metamorphism shape the chemistry of a whole rock.
Mineralogy and crystal structure
Reference formula: Na4Al3Si9O24Cl. Marialite is the sodium- and chlorine-dominant endmember of the scapolite series. Natural scapolite commonly contains meionite component, so composition, optical properties and host rock help identify the exact member. Marialite is classified with silicates and has a tetragonal crystal system. Typical hardness is 5.5–6 on the Mohs scale and specific gravity is approximately 2.5–2.6.
Colour, lustre and habit
Typical colours include colourless, white, grey, yellow, blue. The usual prismatic, granular, massive habit and vitreous, pearly lustre help describe a specimen, but colour alone is not diagnostic.
Formation and notable localities
Marialite forms in or is associated with metamorphic calcareous rocks, skarns, granulites and scapolite-rich alkaline environments. Important documented localities include Italy, Switzerland, Canada, Tanzania, Madagascar and the United States.
A clear scapolite window into metamorphism
Marialite is most compelling when its transparency and prismatic form are paired with a calc-silicate or granulite matrix. It shows how chlorine-bearing fluids and metamorphism shape the chemistry of a whole rock.
Collecting and care
Protect transparent crystals from impact and sudden heat; keep locality and analytical information with the specimen.
