Ari Synthetic Diamond tester by Presidium
Ari Synthetic Diamond tester by Presidium
Ari Synthetic Diamond tester by Presidium
Ari Synthetic Diamond tester by Presidium
Ari Synthetic Diamond tester by Presidium
Ari Synthetic Diamond tester by Presidium
  • Load image into Gallery viewer, Ari Synthetic Diamond tester by Presidium
  • Load image into Gallery viewer, Ari Synthetic Diamond tester by Presidium
  • Load image into Gallery viewer, Ari Synthetic Diamond tester by Presidium
  • Load image into Gallery viewer, Ari Synthetic Diamond tester by Presidium
  • Load image into Gallery viewer, Ari Synthetic Diamond tester by Presidium
  • Load image into Gallery viewer, Ari Synthetic Diamond tester by Presidium

Ari Synthetic Diamond tester by Presidium

Feefo logo

Ref: Ari

Regular price
Sale price
Regular price
Out of stock
Unit price
Shipping calculated at checkout.

(Single item price excluding VAT: £797.92)

Stock: Available

UK company, easy telephone support

Free gift option with this item

Select options

Select your free gift

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


The Presidium ARI is an essential tool for the experienced jeweller and professional diamond dealer, it is for testing known diamonds.

Providing you are quite certain you have a diamond, test it on the Ari to see the chances of it being natural or synthetic. However, the Presidium ARI will not tell you if the stone is simply "not diamond", its purpose is to 'screen' diamonds to see which might be synthetic (see below). 

Natural diamonds grow, naturally, deep in the earth as 'rough' diamond crystals (mined diamonds). Synthetic diamonds are grown by man in a laboratory. Synthetics and naturals are identical, they are both diamond. That is why it is so difficult to tell them apart; that is why these testers are expensive. Find out more about this at our guide to synthetic-diamond testing.

"Synthetic" is the scientific term. Colloquially, we say lab-grown or manmade or lab-created. 

The Presidium ARI will distinguish most synthetic diamond from natural diamonds. It will also detect Moissanite. The Presidium ARI is not a diamond tester for distinguishing diamond from non-diamond, if you need a 'diamond tester, you can find the product here, or see our general guide to buying diamond testers

Guarantee: 1 year


  • comfortably handheld 
  • can test any stone mounted in jewellery (in addition to loose stones)
  • also tests for Moissanite 
  • fast response time (test-result in 3 seconds)
  • left-handed or right-handed use
  • one year guarantee


  • The tester
  • Neat heavy-duty carrying pouch
  • USB power cable (for use instead of batteries)
  • Spare test-tip
  • Calibration disc
  • Stone-holder for loose stones (you can also test stones mounted in jewellery)
  • Polishing cloth (to clean the stone before the test)
  • Alcohol wipes (for cleaning the test-tip)


1) Clean the top (table) of the stone thoroughly with the polishing cloth
2) Insert the probe into the tester
3) Do not remove the cap. Turn it on, wait 10 seconds for it to warm up
4) Remove cap, hold probe on the black disc supplied and wait while it calibrates
5) Place the probe in the centre of the stone as instructed on the display and see the reading (details below).
6) When you have finished all your testing, remove the probe from the tester and put it safely away in its case.


CVD / HPHT / Type IIa diamond
CVD/ HPHT are two are methods of growing diamond = synthetic
Type IIa diamond is a very rare type of natural diamond that will show up as 'synthetic' on this tester. So if the tester shows, "CVD / HPHT / Type IIa Diamond" there is a good chance it's synthetic but this is not guaranteed.

By "diamond" they mean natural diamond. 

Moissanite is not diamond (neither natural diamond nor synthetic diamond) but it is useful to be able to detect these because they show up as diamond on cheap diamond testers. 

You notice that there isn't a reading not diamond ("simulant"); if you are not a diamond dealer or experienced jeweller you must be certain you are testing a stone that will register 'diamond' on most diamond testers; testing non-diamonds on a Synthetic Diamond Tester can give incorrect readings.


Size 190mm X 46mm (1.2 inches) X 25mm 

Weight 60g 

Tests* stones from 0.02 to 10 carats incl. mounted stones in any setting

Tests* stones of colour D to J

Tests* round (brilliant-cut) stones that are perfectly polished

* It is important to understand what these limitations mean, see our guide to synthetic-diamond testing.


Start-up time 10 seconds

Testing time 3 seconds


Power: three AAA batteries (supplied) or any USB power source (USB cable supplied)

Battery life: 4 hours of testing

Auto-power-off yes, if used on battery power it turns itself off after 10mns of non-activity.


Gives correct results about 95% of the time (6% false positive rate, 4.5% false negative rate) providing the colour is 'clear' (colour D to J) and the size is at least 0.02ct and the cut isn't shallow.


1 year

Limitations, please read!

The Presidium ARI is not for testing diamond v. non-diamond. It is for showing you the chance of a diamond being natural (originating from the earth) or synthetic (manmade in a laboratory) - both are 'real' diamond. The ARI also distinguishes diamond from Moissanite.  A synthetic-diamond tester is for the experienced jeweller and professional diamond dealer

5% of natural diamonds have an unusual composition ("Type IIa diamond") and cannot be distinguished from synthetic diamonds. 

Stones must be at least 1.3mm diameter (approx. 0.02ct) so if the stone is small, check it with a diamond gauge. For the non-expert: select a diamond gauge as your free gift. For the professional jeweller: from 3 points is safe.  

Stones must be Brilliant Cut (modern, round) and perfectly-cut in proportion, it will not test shallow stones. For the non-expert: make sure the stone is recent (eg not from the 19th century) and is round. For the professional jeweller: if you specialise in Victorian jewellery (or earlier) this tester might not be suitable, it will not give accurate results on rose-cut etc. 

The stone must be very 'white' in colour (colour D to J).
For the non-expert: if it has any colour (e.g. the tiniest slightest yellow tint) you won't get an accurate reading. It takes an expert to colour-grade a stone, to the non-expert Colour Grade D will look exactly the same as Colour Grade J.  For the professional jeweller: if you work at a shop counter and don't understand this, please ask your diamond expert to colour-grade the stone for you.  

For more information see our guide to synthetic-diamond testing.


    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.

    Further Information

    All about electronic gem testers 
    Gem testers | Quicktest

    Guide to buying and testing diamonds 
    Guide to buying and testing diamonds | Quicktest

    Distinguishing diamond from Moissanite
    Distinguishing diamond from Moissanite | Quicktest

    Testing for synthetic diamonds
    Testing for synthetic diamonds | Quicktest

    Jewellery, hallmarks, gemstones | Quicktest


    Free gift details

    If you would like one of the following free gifts with this product, select one from “Select your free gift” above.

    Plastic Diamond and Pearl Gauge (RRP £2.50 )

    Cz (cubic zirconia). (RRP £5.42 )

    Bottle of Isopropyl for cleaning stones (RRP £2.92 )


    Ask a Question
    • Does it test mounted stones too?

      Yes, that is what is so good about this one, it can test any mounted stones (other models either don't test mounted stones at all, or are limited to small rings).

    • Is it poassible to ship to South Korea? If possible, how much is the shipping fee?

      Yes we can ship to nearly* any country, including South Korea. If you add it to the cart and enter your address, the computer will calculate the cost of shipping.

      * The only exceptions are a handful of remote war-torn countries that have no infrastructure.

    • I am thinking about buying a fairly large diamond (approx 3cts) and want to be absolutely certain it's a natural diamond and not a synthetic one. The seller has a diamond tester which uses thermal conductivity but admitted his tester can sometimes be fooled. Can I rely 100% on this one.

      See our very detailed guide to buying diamond testers

      Your seller is correct about his a thermal conductivity diamond tester, it won't detect if you have a natural diamond or a synthetic diamond. 

      The ARI will tell you, but nothing is 100%.  For instance, the ARI won't give accurate readings on stones with a yellow-ish tint (the colour must be between colour-grades D and J); it won't give accurate readings on very small stones (under 2pts); it won't give accurate readings on with a very narrow pavilion (typically 'simple' cuts from the 17th to 19th centuries).

      In your particular case, since you are buying a very large stone, spending an extra £1000.00 on the ARI won't add much to the price (relatively) and would give you peace-of-mind.

    • I will buy this item and I have £900.00 will you accept my offer?

      No, sorry. 

      We are always interested to know if anyone is selling these significantly cheaper, we expect that our prices are very competitive. Also, we are unique in that we actually check items before dispatch.

    • Would this work with rough stones? I mean rough diamonds ? And show the difference between man made and natural?

      No. ARI will only work on polished diamonds (must be between D – J color).

      The purpose of the Ari is to show the difference between synthetic (man-made in a laboratory) and natural (dug from the ground) diamonds, please read the product description.

      Do not confuse 'synthetic' with simulant/imitation. Read all about it at Testing for Synthetic Diamonds.