touchstone
(ˈtʌtʃstəʊn)
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-coloured variety of quartz or jasper (also called basanite), used for testing the quality of gold and silver alloys by the colour 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 colour, as black marble or basalt. (Cf. touch n. 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 w{supc}{suph} 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. |