The Collaborative International Dictionary
Sinter \Sin"ter\, n. [G. Cf. Cinder.] (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.
Calcareous sinter is a freshwater calcium carbonate deposit, also known as calc-sinter. Deposits are characterised by low porosity and well-developed lamination. Calcareous sinter should not be confused with siliceous sinter, which the term sinter more frequently refers to. It has been suggested that the term "sinter" should be restricted to siliceous spring deposits and be dropped for calcareous deposits entirely.