(p. 208) kaṣa a kind of astringent juice of some plants (কলার কষ); stain caused by this juice (কষ লাগা); tannin; touchstone. 102)

(p. 208) kaṣana1 act of rubbing or itching; act of trying gold and other metals on a touchstone; tanning. 104)

(p. 208) kaṣṭi act of trying or testing (gold etc.) on a touchstone; a touchstone. ̃পাথর n. touchstone. কষ্টিপাথরে যাচাই করা v. to try or test the purity (of gold etc.) by rubbing on a touchstone; to assay (metals). 114)

(p. 568) nikaṣa a streakplate or touchstone; whetstone; whetting; a testing streak of gold. নিকষণ n. act of rubbing or testing (gold) on a touchstone. নিকষিত a. rubbed or tested on a touchstone; polished; found to be genuine by testing on a touchstone, pure, sterling ('নিকষিত হেম'). 23)