FOR BEGINNERS
The Catalogue
Diamond & Gemstone Detectors
Diamonds and coloured stones involve two very different jobs, and they need two different kinds of instrument. The first is verification — you already hold a stone and need to know whether it is a diamond, a moissanite or an imitation before money changes hands. The second is location — searching gem-bearing ground to decide where to dig, wash and sample. This category covers both, and it is worth being clear which one you actually need, because no single device does both.
For verification we stock Presidium handheld testers, the instruments used across gold souks, jewellery workshops and buying offices. They work by contact: a fine probe touches the stone and reads how quickly it carries heat away. Diamond conducts heat far better than almost any imitation, so a thermal tester such as the Diamond Mate A/C or the Gem Tester II separates diamond from glass, cubic zirconia and most simulants in seconds. Moissanite is the exception — it conducts heat much like diamond — which is why the Multi Tester III adds an electrical stage to tell the two apart. These are counter and workshop instruments, not ground-search detectors: they confirm a stone in your hand, not one buried in a field.
For location, most gem-quality diamonds and coloured stones are non-metallic and non-conductive, so a conventional VLF or pulse-induction metal detector will not respond to the stone itself the way it does to gold or coins. What exists instead is long-range locating equipment, which scans a wide area and indicates a search direction toward a suspected deposit. We source these to order rather than stocking them, and we are honest about the limits: a locator narrows the ground worth working, it does not confirm a single buried stone at a precise depth, and any seller promising that is not being truthful. It pays off only in genuine gem-bearing geology — alluvial gravels, riverbeds and kimberlite zones — alongside sampling, panning and washing.
AO Gold Detectors is a Dubai-based authorised reseller and importer, shipping genuine, warranty-backed equipment across Africa and the Middle East. There is no online card checkout — you order and ask questions directly on WhatsApp in Arabic, French or English, and we will tell you honestly whether a tester, a locator, or neither is the right spend for your situation.
3 products · Presidium
Singapore
How to choose
- Decide which job you need first: a tester verifies a stone you already hold, a locator searches ground you have not dug yet. They are different instruments and one will not do the other's work.
- For buying and trading stones, a thermal-conductivity tester is the everyday tool — the Presidium Diamond Mate A/C and Gem Tester II separate diamond from glass, cubic zirconia and most imitations in seconds with a single probe touch.
- If moissanite is a risk in your market — and increasingly it is — choose a dual electro-thermal instrument such as the Multi Tester III, because moissanite conducts heat almost like diamond and will pass a thermal-only tester.
- Technique matters more than price with contact testers: clean and dry the stone, let it reach room temperature, hold the probe perpendicular with steady light pressure, and use a fine tip for small or set stones. A rushed reading is the main cause of a wrong answer.
- Know what long-range locating can and cannot do: it indicates a search direction over large areas to help you prioritise where to dig and sample — treat it as a field aid, not an X-ray that confirms a single buried stone.
- Start from your geology: locating equipment pays off only in genuine gem-bearing ground — alluvial gravels, riverbeds and kimberlite zones — so confirm your area is known for stones, and pair any locator with sampling, panning and washing.
- Buy genuine and ask first: message us on WhatsApp in your language to confirm a brand-new, warranty-backed unit, and we will advise honestly on whether this equipment fits your ground and your budget.
Frequently asked questions
Can a metal detector find diamonds or gemstones?
Generally no. Diamonds and most precious gemstones are non-metallic and non-conductive, so a standard VLF or pulse-induction metal detector — which responds to metal — will not detect the stone itself. If you want to check a stone you already have, that is the job of a contact tester like the Presidium units on this page. If you are searching ground, gem prospecting still relies mainly on geology, sampling, panning and washing gravels, with a long-range locator used only to indicate which areas are worth working.
What is the difference between a diamond tester and a diamond locator?
A tester is a contact instrument: you touch a fine probe to a stone you are already holding and it tells you within seconds whether that stone carries heat — and, on a dual model, electricity — the way a diamond does. A locator is a field-search device that scans open ground and indicates a direction worth investigating. A tester gives you a definite answer about one stone; a locator gives you a place to start digging. Most buyers, jewellers and souk dealers need the first; prospectors working known gem ground may want both.
Will a thermal tester tell diamond from moissanite?
A thermal-only tester will not, and this catches people out. Moissanite carries heat at a rate close enough to diamond that a single-stage thermal probe can read it as diamond. To separate them you need an instrument that also measures electrical conductivity — the Presidium Multi Tester III tests electro-thermally for exactly this reason, so moissanite is identified rather than mistaken. If you buy stones from the public, this is the tester to have.
How do long-range diamond and gemstone locators actually work?
Long-range locators are designed to scan a large area and indicate a direction toward a suspected deposit, helping you decide where to concentrate your digging and testing rather than searching blindly. They are a field-search aid, not a confirmation device — they do not tell you a single stone is at a precise spot and depth. We are honest about this: the locator narrows the ground, and hands-on prospecting (sampling, panning, washing) confirms whether stones are actually there.
Where in Africa and the Middle East is this equipment useful?
It is most useful in genuine gem-bearing geology — alluvial gravels, riverbeds and kimberlite zones across Central and West Africa and parts of the wider MENA region, where diamonds and gemstones have historically been found. The equipment does not create deposits; it only helps you work ground that is already known or strongly suspected to carry stones. If you are unsure whether your area qualifies, tell us where you prospect on WhatsApp and we will give you an honest view.
Are these locators a guaranteed way to get rich quickly?
No, and we will never sell them that way. Finding diamonds and gemstones takes the right geology, fieldwork, patience and often a licence to dig — a locator is one tool among several, not a shortcut. Anyone advertising guaranteed finds, exact depths for stones or instant riches is being dishonest. We would rather set realistic expectations and recommend the right equipment for serious prospectors than oversell a device.
Are these genuine, and how do I order?
Yes. The Presidium testers listed here are genuine, brand-new units with manufacturer warranty, held in Dubai. Long-range locators are sourced to order from reputable manufacturers on the same terms. There is no online card checkout — you enquire directly on WhatsApp in Arabic, French or English, and our team confirms availability, configuration, price and delivery to your country. We would rather set realistic expectations than oversell a device.
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