Nabesite

Nabesite is a rare silicate mineral of the zeolite group with the chemical formula Na₂BeSi₄O₁₀·4(H₂O). It occurs as colorless to white orthorhombic crystals in thin platy mica like sheets. It has the zeolite structure. Its Mohs hardness is 5 to 6 and its specific gravity is 2.16. The reported refractive index values are n_α=1.499, n_β=1.507, and n_γ=1.511.

It was discovered in the Ilimaussaq intrusive complex, of southwest Greenland, and first recognized in 2000. It occurs in tugtupite-bearing albitite, a rare highly alkaline igneous rock.