Nabesite is a rare silicate mineral of the zeolite group with the chemical formula Na<sub>2</sub>BeSi<sub>4</sub>O<sub>10</sub>÷4(H<sub>2</sub>O). 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<sub>ñ</sub>=1.499, n<sub>ò</sub>=1.507, and n<sub>ó</sub>=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.