{"product_id":"gold-test-needles-set-10k-14k-18k-999-silver","title":"Gold Test Needles-Set Of Four-10K-14K-18K \u0026 .999 Silver","description":"\u003cp\u003eGold test needles are an essential tool for jewelers performing acid-based metal testing. This set of four needles covers three gold karats — 10K, 14K, and 18K — plus .999 fine silver, giving you a reliable reference for the most commonly tested metal finenesses.\u003c\/p\u003e\n\n\u003cp\u003eTo use, select the appropriate karat needle and rub or scratch it against a test stone. Make a corresponding scratch or rubbing with the item being tested alongside the needle mark. Apply a drop of testing acid across both marks and observe the reactions. If the item reacts identically to the needle mark, the karat or fineness may be the same. If the item dissolves faster than the needle mark, the gold content may be lower; if it dissolves slower, the gold content may be higher. For silver testing, a dedicated silver test acid is required.\u003c\/p\u003e\n\n\u003cp\u003ePlease note: acid-based metal testing is subjective and requires careful observation and practice to master consistently.\u003c\/p\u003e\n\n\u003ch3\u003eFeatures\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003eSet of four test needles for comparative acid testing\u003c\/li\u003e\n  \u003cli\u003eCovers three gold karat standards: 10K, 14K, and 18K\u003c\/li\u003e\n  \u003cli\u003eIncludes one .999 fine silver needle for silver testing\u003c\/li\u003e\n  \u003cli\u003eUsed alongside a test stone and testing acid to compare metal reactions\u003c\/li\u003e\n  \u003cli\u003eEnables visual comparison of acid dissolution rates to estimate karat or fineness\u003c\/li\u003e\n  \u003cli\u003eSilver needle requires a separate silver test acid for accurate results\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eSpecifications\u003c\/h3\u003e\n\u003ctable\u003e\n  \u003ctr\u003e\n\u003cth\u003eSet Contents\u003c\/th\u003e\n\u003ctd\u003e4 test needles\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003cth\u003eKarat Standards Included\u003c\/th\u003e\n\u003ctd\u003e10K, 14K, 18K gold; .999 silver\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003cth\u003eProp 65\u003c\/th\u003e\n\u003ctd\u003eContains Lead; Contains Lead and Phthalates\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\n\n\u003ch3\u003eNotes\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003eAcid-based metal testing is entirely subjective, and results should be interpreted with care.\u003c\/li\u003e\n  \u003cli\u003eMastery of this testing method requires practice and careful observation.\u003c\/li\u003e\n  \u003cli\u003eA test stone and appropriate testing acids are required and are not included.\u003c\/li\u003e\n  \u003cli\u003eSilver testing requires a dedicated silver test acid.\u003c\/li\u003e\n  \u003cli\u003eThis product is subject to California Proposition 65 warnings for Lead and Phthalates.\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Otto Frei","offers":[{"title":"Default Title","offer_id":43581618487510,"sku":"156.706","price":88.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0609\/9832\/0342\/files\/gold-test-needles-set-of-four-10k-14k-18k-and-999-silver-otto-frei.jpg?v=1719957494","url":"https:\/\/www.ottofrei.com\/products\/gold-test-needles-set-10k-14k-18k-999-silver","provider":"Otto Frei","version":"1.0","type":"link"}