{"product_id":"premium-gold-test-stone-thick-arkansas-novaculite-usa","title":"Premium Gold Test Stone-Thick-Made in the USA- 2-1\/2\" X 1-1\/2\" X 1\/2\"","description":"\u003cp\u003eA professional-grade gold testing stone for precious metal identification, this \u003cstrong\u003ethick touchstone\u003c\/strong\u003e is made in the USA from natural Arkansas black novaculite — a premium material quarried and cut domestically. At 2-1\/2\" × 1-1\/2\" × 1\/2\", the generous thickness provides a durable, long-lasting testing surface suited for daily bench use.\u003c\/p\u003e\u003cp\u003eAlso referred to as streak stones or touchstones, this tool is a trusted standard for jewelers performing acid-based precious metal testing. Beware of cheap imitations made of glass, which stain quickly and degrade with repeated use. Natural novaculite provides a consistent, stable surface that holds up to professional demands.\u003c\/p\u003e\u003ch3\u003eFeatures\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eMade in the USA from natural Arkansas black novaculite\u003c\/li\u003e\n\u003cli\u003eThick profile (1\/2\") for extended service life and durability\u003c\/li\u003e\n\u003cli\u003eSmooth, consistent surface ideal for precise streak testing\u003c\/li\u003e\n\u003cli\u003eResistant to staining and degradation — unlike glass imitations\u003c\/li\u003e\n\u003cli\u003eCompatible with acid-based precious metal testing methods\u003c\/li\u003e\n\u003cli\u003eSuitable for comparative karat testing using reference needles or known gold samples\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eHow to Use\u003c\/h3\u003e\u003col\u003e\n\u003cli\u003eRub or scratch the item to be tested across the stone surface to leave a metallic streak.\u003c\/li\u003e\n\u003cli\u003eApply testing acid (sold separately) across the streak.\u003c\/li\u003e\n\u003cli\u003eObserve the acid reaction — an experienced user can determine metal type based on how the streak responds.\u003c\/li\u003e\n\u003cli\u003eFor comparative karat testing, rub a reference needle or known gold sample beside the test streak, apply acid to both, and compare reactions. A similar reaction indicates similar karat content.\u003c\/li\u003e\n\u003c\/ol\u003e\u003ch3\u003eSpecifications\u003c\/h3\u003e\u003ctable\u003e\n\u003ctr\u003e\n\u003cth\u003eDimensions\u003c\/th\u003e\n\u003ctd\u003e2-1\/2\" × 1-1\/2\" × 1\/2\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eMaterial\u003c\/th\u003e\n\u003ctd\u003eNatural Arkansas black novaculite\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eOrigin\u003c\/th\u003e\n\u003ctd\u003eMade in the USA\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eTesting Acid\u003c\/th\u003e\n\u003ctd\u003eSold separately\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\u003ch3\u003eNotes\u003c\/h3\u003e\u003cp\u003eTesting acid and gold testing needles are \u003cstrong\u003enot included\u003c\/strong\u003e and must be purchased separately. Accurate metal identification via acid testing requires experience and familiarity with acid reaction results. For comparative karat testing, use reference needles or gold samples of verified karat content.\u003c\/p\u003e","brand":"Otto Frei","offers":[{"title":"Default Title","offer_id":43581741957334,"sku":"156.710.5","price":41.75,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0609\/9832\/0342\/files\/premium-gold-test-stone-thick-made-in-the-usa-2-12-x-1-12-x-12-otto-frei.jpg?v=1719957418","url":"https:\/\/www.ottofrei.com\/products\/premium-gold-test-stone-thick-arkansas-novaculite-usa","provider":"Otto Frei","version":"1.0","type":"link"}