Sinter n. (Min.) Dross, as of iron; the scale which files from iron when hammered; applied as a name to various minerals. Calcareous sinter, a loose banded variety of calcite formed by deposition from lime-bearing waters; calcareous tufa; travertine.
Ceraunian sinter, fulgurite.
Siliceous sinter, a light cellular or fibrous opal; especially, geyserite (see Geyserite). It has often a pearly luster, and is then called pearl sinter.