{"product_id":"gold-test-needles-set-8k-10k-12k-14k-18k","title":"Gold Test Needles-Set Of Five-8K-10K-12K-14K \u0026 18K","description":"\u003cp\u003eGold test needles are an essential tool for jewelers and precious metal buyers who need to verify the karat purity of gold items using acid testing. This set includes five needles spanning the most commonly encountered gold karats — 8K, 10K, 12K, 14K, and 18K — giving you a comprehensive reference range for comparative acid testing.\u003c\/p\u003e\n\n\u003cp\u003eTo use, select the appropriate karat needle and rub or scratch it against a test stone. Make a second mark on the stone with the item being tested, placing both marks side by side. Apply a drop of testing acid across both marks and observe how each reacts. If the item being tested reacts identically to the test needle mark, the karat of the two pieces may be the same. If the item dissolves more quickly than the test needle mark, the gold content may be lower than the selected needle's karat. If the item dissolves more slowly, the gold content may be higher. Please note that acid testing of this type is entirely subjective and requires careful observation and practice to master.\u003c\/p\u003e\n\n\u003ch3\u003eFeatures\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003eSet of five gold test needles covering 8K, 10K, 12K, 14K, and 18K\u003c\/li\u003e\n  \u003cli\u003eUsed for comparative acid testing on a test stone\u003c\/li\u003e\n  \u003cli\u003eAllows side-by-side comparison of acid reactions between known and unknown gold items\u003c\/li\u003e\n  \u003cli\u003eSpans a wide karat range to support identification across common gold purities\u003c\/li\u003e\n  \u003cli\u003eA practical reference tool for jewelers, appraisers, and precious metal buyers\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eSpecifications\u003c\/h3\u003e\n\u003ctable\u003e\n  \u003ctr\u003e\n\u003cth\u003eSet Quantity\u003c\/th\u003e\n\u003ctd\u003e5 needles\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003cth\u003eKarats Included\u003c\/th\u003e\n\u003ctd\u003e8K, 10K, 12K, 14K, 18K\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003cth\u003eTesting Method\u003c\/th\u003e\n\u003ctd\u003eComparative acid testing on a test stone\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003cth\u003eCalifornia Prop 65\u003c\/th\u003e\n\u003ctd\u003eWarning: Contains lead and phthalates\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\n\n\u003ch3\u003eWhat's Included\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e8K gold test needle\u003c\/li\u003e\n  \u003cli\u003e10K gold test needle\u003c\/li\u003e\n  \u003cli\u003e12K gold test needle\u003c\/li\u003e\n  \u003cli\u003e14K gold test needle\u003c\/li\u003e\n  \u003cli\u003e18K gold test needle\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eNotes\u003c\/h3\u003e\n\u003cp\u003eAcid testing with test needles is a subjective method, and results depend on careful observation and practiced technique. Testing acid and test stone are not included and must be obtained separately. This product contains lead and\/or phthalates — see California Proposition 65 for details.\u003c\/p\u003e","brand":"Otto Frei","offers":[{"title":"Default Title","offer_id":43581745529046,"sku":"156.709","price":79.95,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0609\/9832\/0342\/files\/gold-test-needles-set-of-five-8k-10k-12k-14k-and-18k-otto-frei.jpg?v=1719957417","url":"https:\/\/www.ottofrei.com\/it\/products\/gold-test-needles-set-8k-10k-12k-14k-18k","provider":"Otto Frei","version":"1.0","type":"link"}