Iona Chemistry

The nephrite of Iona has a specific gravity of 2.595, H 3.5, SiO3 44.85, MgO 36.05, FeO 3.6, Al2O3 1.3, HO 13.55. — Cyclopaedia of Chemistry with Its Applications to Mineralogy, Physiology, and the Arts, Robert Dundas Thomson, Griffin and Company, 1854, page 379.