kopin.

1898 D. W. Carnegie Spinifex & Sand ii. ii. 42 We came on a small tract of ‘kopi country’ (powdered gypsum).

1898 D. W. Carnegie Spinifex & Sand ii. ii. 43 This kopi is peculiar soil to walk over.

1898 D. W. Carnegie Spinifex & Sand iii. iii. 91 A sort of powdery gypsum, called ‘Kopi’ by the natives.

1936 A. Russell Gone Nomad ix. 71 The drying bed of the lake was composed of a clinging kopi mud that would have enmeshed a duck.

1957 D. Niland Call me when Cross turns Over i. 8 The lie of all that barren land he knew, the shelves, the pits, the mullock dumps of kopi, every mound and every rise and fall.

1971 J. S. Gunn Opal Terminol. 24 Kopi, gypsum which sometimes carries good opal. In L. Ridge the kopi is different, being flattish crystals of silenite, rather than the gypsum clay of S. Aust. and Qld.