Multi Tester III

The Presidium Multi Tester III (PMuT III) is a handheld contact instrument for the jewellery counter — not a ground-search detector. It combines two measurements in a single retractable probe: thermal conductivity, which separates diamond from most colourless simulants, and electrical conductivity, which is the only dependable way to tell diamond from moissanite. Moissanite conducts heat almost as well as diamond and routinely fools thermal-only pens; the electrical reading settles it. Touch the tip to a clean, dry stone and the 180-degree LED display and audible tone report diamond, moissanite, another stone, or metal. Presidium states the 0.6 mm retractable tip is the industry's thinnest, which lets the instrument read stones from 0.02 ct — melee, pavé and stones still in their mounting. A metal alert buzzer tells you when the tip has landed on the setting instead of the stone, so an invalid reading is obvious. The body is ambidextrous with a rubberised anti-slip grip, measures 165 × 25 × 40 mm and weighs 54 g without batteries; three AAA cells give roughly seven hours of continuous use, with automatic power-off and a low-battery indicator, and an AC port accepts Presidium's power adaptor (sold separately). Presidium specifies an optimal working range of 18–27 °C, worth remembering in Gulf and Sahel shops: let the instrument and the stone settle indoors before testing. It verifies stone identity only — it does not grade colour, clarity or weight, and it cannot locate buried metal.