{"product_id":"premium-gold-test-stone-arkansas-novaculite-usa-2-5x1-5x0-25in","title":"Premium Gold Test Stone-Made in the USA 2-1\/2\"  X 1-1\/2\" X  1\/4\"","description":"\u003cp\u003e\u003cstrong\u003ePremium Gold Test Stone – Made in the USA\u003c\/strong\u003e – 2-1\/2\" × 1-1\/2\" × 1\/4\"\u003c\/p\u003e\u003cp\u003eThis top-quality gold testing stone is an essential tool for precious metal identification. Made from natural Arkansas black novaculite quarried and cut in the USA, it is also commonly referred to as a streak stone or touchstone. Unlike cheap imitations made of glass that quickly stain and degrade, this premium stone is built to deliver reliable, long-lasting performance in professional settings.\u003c\/p\u003e\u003cp\u003eTo use, rub or scratch the item to be tested across the surface of the stone, then apply testing acid (sold separately) over the rubbing. An experienced user can determine the metal type based on the acid's reaction to the streak. For comparative karat testing, rub a known gold testing needle or verified gold sample alongside the test item's streak, then apply acid to both. A similar reaction indicates a similar karat level.\u003c\/p\u003e\u003ch3\u003eFeatures\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eMade from natural Arkansas black novaculite – quarried and cut in the USA\u003c\/li\u003e\n\u003cli\u003ePremium quality construction resists staining and degradation\u003c\/li\u003e\n\u003cli\u003eSuperior alternative to glass-based imitation test stones\u003c\/li\u003e\n\u003cli\u003eAlso known as a streak stone or touchstone\u003c\/li\u003e\n\u003cli\u003eSuitable for comparative karat testing using gold testing needles or known gold samples\u003c\/li\u003e\n\u003cli\u003eCompatible with standard precious metal testing acids (sold separately)\u003c\/li\u003e\n\u003c\/ul\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\/4\"\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\u003eVariants\u003c\/th\u003e\n\u003ctd\u003eSingle variant\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\u003ch3\u003eNotes\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eTesting acid is required for use and is sold separately.\u003c\/li\u003e\n\u003cli\u003eAccurate karat determination requires experience interpreting acid reactions.\u003c\/li\u003e\n\u003cli\u003eFor comparative testing, gold testing needles or verified gold samples of known karat are required and are not included.\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Otto Frei","offers":[{"title":"Default Title","offer_id":43581617766614,"sku":"156.710","price":37.9,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0609\/9832\/0342\/files\/premium-gold-test-stone-made-in-the-usa-2-12-x-1-12-x-14-otto-frei.jpg?v=1719957494","url":"https:\/\/www.ottofrei.com\/products\/premium-gold-test-stone-arkansas-novaculite-usa-2-5x1-5x0-25in","provider":"Otto Frei","version":"1.0","type":"link"}