ARCUS diamond tester (also tests Moissanite, ruby, sapphire) - by Gemtrue

Summary The ARCUS is absolutely the most accurate of all* the low-cost diamond tester; it is the only 'simple' tester that isn't fooled by our own selection of 'difficult' stones. This is due to its exceptional built-in UV light which detects the latest low-conductivity Moissanites; most* other testers show these Moissanites to be 'diamond'.  * all testers, excluding the specialist synthetic-diamond testers which cost between £750.00 and £1000.00. Tests for diamond and Moissanite and ruby/sapphire. The top of the tester lights up with the name of the stone (and a different colour for each).  Guarantee, 1 year. Every diamond tester ever made has its limitations. For standard diamond testing see our article Guide to Buying Diamond Testers. None of these can distinguish natural (mined) diamonds from synthetic (lab-grown) diamonds, both are diamond - for these you will require a specialist tester, see Testing for Synthetic Diamonds. Synthetic is not to be confused with simulant which is "anything you may think looks like diamond even though it isn't" - for which standard testers such as the ARCUS are designed.  Technical PHYSICAL Dimensions: 7½ X 1 X 1½ inches (185 X 25 X 30mm) Weight: 100g Tip: can test stones down to 0.02ct (2pt) in size.  Operating temperature: recommended between 18 and 27 degrees C (64 to 81 degrees F). Though tests show it works fine down to 15 degrees C. (59 degrees F). RESPONSE TIME Warm-up time when switched on: 15 to 20 seconds Testing: result in 1 or 2 seconds Warm-up time between tests: 2 or 3 seconds POWER  One PP3 battery (supplied). Optional 9 volt power supply (mains adaptor) Battery life: don't know, a few thousand tests? Low-battery indicator: none, when it fails to warm up, it needs a new battery Auto-shut-off: yes, it bleeps then turns itself off if not used for five minutes. ACCESSORIES / PRESENTATION  fitted case carrying strap stone-holder polishing cloth (to remove any surface grease-free before testing) instructions unique system for recording the readings (no app. required): a note pad RELIABILITY For testing diamonds and Moissanite, estimate, you would get the correct result 95% of the time. This will change over the months and years as the manufacturers of Moissanite tweak the formula. Disclaimer All testers  must be used in conjunction with the user's skill, knowledge and experience. Under no circumstances shall QUICKTEST be liable for direct or indirect loss sustained in connection with any item. Nothing is 100% accurate, you must understand the limitations of any tester you buy. We also suggest you regularly test known samples to check for any obvious faults. Full support given for items you buy from QUICKTEST. Alternatives The ARCUS distinguishes diamond from non-diamond (simulant/imitation).  It will not distinguish natural (mined) diamond from synthetic (lab-grown) diamond - that requires a very specialist tester (£700.00 to £1000.00) see ARI, ARETE and APEX. It is important not to confuse "Synthetic" with "simulant", see technical terms.  For a summary of all diamond and gem testers see the Comparison Chart, or see a more detailed explanation of what the various types of tester can (and can't) detect at our Guide to Buying Diamond Testers.