Diamond selector II (3 month guarantee only)
Diamond selector II (3 month guarantee only)
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Diamond selector II (3 month guarantee only)

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Ref: DT-DS-crp

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(Single item price excluding VAT: £8.68)

Stock: Available

UK company, easy telephone support

Pickup available from Quicktest (WD18 8JA)
Email us or call on 01923-220206 for appointment.


All Diamond Selector testers look the same but the quality of the construction and the components varies. This is the very cheapest diamond tester, as seen on eBay and Amazon. We will guarantee it against breakdown for 3 months but you may not return it because it often gives incorrect results, this is what you get for £12.50 (irrespective of what any seller might tell you!). 

  • Maybe OK for someone who is going to test a couple of stones just to confirm what they already think (that they are or are not diamond)...then never use it again. 
  • Certainly OK or anyone who wants the cheapest tester in existence. 
  • Standard format, nearly everyone who has used a diamond tester is familiar with how to use this one
  • Adjustable sensitivity, so you can (within limits) use it in cold conditions
  • It does not test for Moissanite (a manmade stone that is not diamond) - Moissanite shows up as diamond on this tester.

See also, everything you need to know about testing diamonds in the Guide to buying diamond testers. 


Turn it on, wait for it to warm up, very carefully set the sensitivity according to the chart  (this is very fiddly), place tip in the very centre of the stone, note how high (and at what speed) the LEDs light up.

Providing you have set the sensitivity correctly, on diamond the row of LED lights shoot up to the end and it bleeps; on most other stones nothing at all happens.  The lights can move slightly on ruby and sapphire but this does not 'prove' you have a ruby or sapphire, the LEDs will light up on any very cold stone, any large stone that is cool, and any stone at all if the sensitivity isn't set correctly. It will always register diamond on the manmade stone Moissanite. 



Size: 6¼"X1½"X¾" 155X38X20mm

Weight: 60g

Tests stones down to about 0.05ct (5pt) in size

Operating temperature: recommended between 20 and 25 degrees C , not reliable at lower or higher temperatures. 


Warm-up time anywhere from 20 to 40 seconds depending on the temperature.

Testing time 2 to 4 seconds, approx. (can be hesitant)  

Warm-up time between tests anywhere from 5 to 15 seconds depending on the temperature


Power: one PP3 battery (NOT SUPPLIED)

Battery life: unknown. 

Auto-shut-off: none, i.e. if you forget to turn it off the battery will go flat quite quickly.

Low-battery indicator: none, if the lights fade or flash erratically, or if you get incorrect readings - try changing the battery. 


Carrying case

Poorly-written instructions. 


This is a diamond-only tester, it will not test Moissanite, that means Moissanite will register 'diamond' (for other models see the ALTERNATIVES tab). 

We do test these before dispatch, because many of them don't work, even when new, so we want to be sure the one we send you does work. We could guess, from the quality, that it will give a correct reading 60% to 70% of the time. There's a  high probability that it will break down in less than a year, hence the 3 month guarantee. 

There is nothing special about this 'cheap' diamond tester, this is what you get for £12.50 (in fact, this is what you get for under £20.00!) irrespective of where you buy it or what the seller tells you. 


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.


Please note, none of these testers will distinguish natural stones from synthetic stones. "Synthetic" is a scientific term meaning 'made by man in a factory/laboratory to the same formula found in nature'. The two are usually indistinguishable, synthetic diamond is diamond (read about synthetic diamond testers and see our ARI and ARETE models).

The testers below are to distinguish diamond from non-diamond (simulant/imitation).   


Tests mounted stones [1]

Tests  Diamond

Tests  Moissanite

Ruby / 

Other stones

Diamond selector II  (DT-DS)
(cheap but works most of the time)

Shows up as diamond


No reaction on non-diamond

Diamond Experior (best diamond-only tester) Shows up as diamond Non-diamond reads 'Other Stone'

Moissanite tester by GemVue (Moissanite Plus) MOISS-4)

You must only test stones you are certain are diamond

Multi tester. Experior by Gemtrue (MULTI-EXP)


No reaction on other stones

SAM multi-tester (MULTI-SAM)

Non-diamond reads ‘simulant’

Handheld presidium gem tester (GEMTEST-PGI)

Shows up as diamond

31 stones

Standard Presidium (GEMTEST-P2)

Shows up as diamond

17 stones

Presidium Duo gem tester (GEMTEST-DUO-II)



Digital refractometer by Presidium (REFRACT-DIGI-PRESID)

55 stones

Refractometer (optical not electronic) (Refract-L)

Hundreds of stones [4]

[1] All testers test loose stones but not all can test mounted (set in jewellery) stones.

[2] The probe / analogue meter will test mounted stones, the digital meter will only test loose stones.

[3] The probe / analogue meter: 17 stones; the digital meter: 40 stones.

[4] Skill and practice is required to use an optical refractometer, instructions are not included, see any textbook about gemmology…or the internet.  



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