pumiceousadj.

1676 H. More Remarks 2 Disc. 10 If one side be pumiceous..and the other metalline, the metalline will gravitate on the pumiceous or spungie side.

1772 R. Brookes New Syst. Nat. Hist. (ed. 2) V. xxxiv. 273 There are several kinds of Pyrites... Some..are spongy and shining or pumiceous.

1794 R. Kirwan Elements Mineral. (ed. 2) I. 416 I should..call them pumiceous mixtures.

1845 C. Darwin Jrnl. (ed. 2) viii. 171 These beds are covered by others of a peculiar soft white stone, including much gypsum, and resembling chalk, but really of a pumiceous nature.

1869 J. Phillips Vesuvius ii. 35 Pompeii was overwhelmed with light-coloured pumiceous lapilli.

1885 Manufacturer & Builder 17 82/2 If the cavities are few in number, the texture is called vesicular; if they are more numerous..it is called scoriaceous; and if these cavities predominate, the texture is called pumiceous.

1924 C. Mackenzie Old Men of Sea xvi. 269 A deep bed of light-coloured pumiceous tuff mixed with great blocks of pumice and obsidian and fragments of andesite.

1970 Nature 17 Oct. 254/1 Most of the glass particles are of either regular or pumiceous habit.

2005 Geomorphology 66 240/1 The resulting sequences, formed by ashy and pumiceous layers alternating with buried horizons of soils, dip at an angle similar to the bedrock surface.