Forms: see TOUCH v. [f. TOUCH- 1 + STONE: cf. OF. touchepierre, F. pierre de touche, Sp. piedra de toque.]
1. A very smooth, fine-grained, black or dark-colored variety of quartz or jasper (also called BASANITE), used for testing the quality of gold and silver alloys by the color of the streak produced by rubbing them upon it; a piece of such stone used for this purpose.
1530. Palsgr., 282/1. Touch stone to prove golde with.
1754. Phil. Trans., XLVIII. 664. The difference in colour of these compositions was much less conspicuous on the touchstone.
1812. J. Smyth, Pract. of Customs (1821), 262. Touchstone is the Basaltes, a heavy hard stone, of a very fine texture, of a deep glossy black, resembling that of polished steel.
1908. H. B. Morse, Trade Chinese Emp., 149. A silver commercially pure, as shown by the crude methods of the touchstone.
b. fig. That which serves to test or try the genuineness or value of anything; a test, criterion.
a. 1533. Frith, Another Bk. agst. Rastell (1829), 216. Lay them to the touchstone, and try them with God’s word.
1535. Coverdale, Ecclus. vi. 21. Vnto soch she is as it were a twichstone, & he casteth her from him in all the haist.
1677. Govt. Venice, 106. Therefore it is that Venice is called the School and Touchstone of Embassadors.
a. 1720. Sheffield (Dk. Buckhm.), Wks. (1753), II. 207. Time … in all matters of writing, is the only true touchstone of merit.
1822. Hazlitt, Table-t., I. xi. 253. Well-digested schemes will stand the touchstone of experience.
1871. Blackie, Four Phases, i. 42. The touchstone … to distinguish the true man … from the false pretender.
2. Applied to other stones of similar texture and color, as black marble or basalt. (Cf. TOUCH sb. 6.)
1481–3. Acc. Exch. K. R., Bd. 496. No. 26 (MS.). Ultra lv dolijs lapidum de Cane,… et xxxiij doliis de Touchstone.
1509. Hawes, Past. Pleas., xxxv. (Percy Soc.), 184. Into the castell of olde foundacion, Walled about with the blacke touche stone.
1584. in Willis & Clark, Cambridge (1886), I. 294. The pece of tutch stone wch my Ladye Bacon hath gyven vnto this woorke.
1607. Topsell, Four-f. Beasts (1658), 377. Upon the steps of the Capitol of Rome, there were two Lions of black Marble touch-stone.
a. 1647. Habington, Surv. Worc., in Worcs. Hist. Soc. Proc., I. 102. All … wrytten in Tuchstone with letters of goulde.
1670. Pettus, Fodinæ Reg., 1. If common Stones onely are found (as Marble, Touchstone, Freestone, etc.) we call them Quarries, and not Mines.
1845. Parker, Gloss. Archit., Touch-stone [is] a name sometimes applied to compact dark-coloured stones, such as Purbeck and Petworth marble … frequently used for fine work in Gothic architecture.
