- Any one of a family of hydrous alkali-aluminum silicate minerals, whose crystal lattice may enclose or sequester cations of sodium, potassium, magnesium, calcium, strontium, or barium, or a corresponding synthetic compound, used chiefly as molecular filters and ion-exchange agents.
- A generic name of a group of hydrated double silicates in which the principal bases are aluminium and calcium or sodium.
- A term now used to designate any one of a family of minerals, hydrous silicates of alumina, with lime, soda, potash, or rarely baryta. Here are included natrolite, stilbite, analcime, chabazite, thomsonite, heulandite, and others. These species occur of secondary origin in the cavities of amygdaloid, basalt, and lava, also, less frequently, in granite and gneiss. So called because many of these species intumesce before the blowpipe.
- needlestone; natrolite.
- Any of several <xref>minerals</xref>, <xref>aluminosilicates</xref> of <xref>sodium</xref>, <xref>potassium</xref>, <xref>calcium</xref> or <xref>magnesium</xref>, that have a <xref>porous</xref> structure; they are used in <xref>water softeners</xref> and in <xref>ion exchange chromatography</xref>.
- any of a family of glassy minerals analogous to feldspar containing hydrated aluminum silicates of calcium or sodium or potassium; formed in cavities in lava flows and in plutonic rocks