† rock petren.
Obsolete. rare.
= roche petre n.
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the world > the earth > minerals > types of mineral > nitrates > [noun] > potassium nitrate
nitrumOE
salpetrec1325
sal-nitre1416
saltpetre1501
peter in roche1554
salt nitre1601
nitre1617
roche petre1634
rock petre1667
Smyrna earth1735
nitre crystal1869
1667 T. Henshaw in T. Sprat Hist. Royal-Soc. 264 I my self..have drawn very good Rock peter out of those Stiriæ, which are usually found hanging like Icycles in Arched-cellars and Vaults.
1736 N. Bailey Dict. Domesticum sig. E6 Take five handfuls of common salt, three handfuls of bay salt, and rock petre and petre salt of each one handful.
This entry has been updated (OED Third Edition, June 2010; most recently modified version published online September 2018).
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