A nésosilicate (νήσος nesos “island”) is a Minéral of the family of the Silicate S whose grouping (SiO₄) ^4- associated with a positively charged grouping constitutes the reason Cristal basic flax.

Among the nésosilicates, one finds in particular:

• the Zircon ZrSiO₄;
• the Olivine S (Mg, Fe) ₂SiO₄;
• Garnet-red S X²⁺₃Y³⁺₂ (SiO₄) ^4-₃, where X and Y are ions respectively charged with 2 and 3 positive loads).