One of the properties of natural Diamond is the ability to conduct heat very rapidly, unlike all common Diamond Simulants, such as Glass and Cubic Zirconia, which are typically poor conductors of heat. Ceres Electronics was first to recognize the importance of this significant difference in thermal conductivity as a practical, simple method of gem identification. The thermal gem-testing technique, developed and patented by Ceres Electronics, is now universally accepted by gem and jewelry professionals as a fast simple method of differentiating natural Diamond from its common Simulants


The CZeckpoint has been designed to assist the professional jeweler and gemologist who can visually identify older Diamond Simulants such as YAG, Sapphire, or Titanite, but who may have some difficulty in spotting CZ and Moissanite gems, particularly smaller stones set in gold or silver. For this purpose the CZeckpoint provides a fast, reliable and universally accepted method to confirm the user´s judgment. While Ceres thermal conductivity tester have been proven themselves as inexpensive and practical aids to identify diamond-like gems, positive identification should be confirmed by the use of more sophisticated methods of evaluation, coupled with the experienced skills and judgment of the user.

Please Note:

The Czeckpoint is NOT intended to identify Moissanite. For proper identification of Moissanite, the user must use the Czeckpoint in tandem with the Ceres Secure II Moissanite Detector.


The Czeckpoint will operate on either a Nickel-Cadmium rechargeable battery pack or from an electrical outlet. Both the battery pack and AC adaptor are provided with the unit. Please Note that the Czeckpoint´s battery pack MUST be attached even if you intend to operate the unit from an electrical outlet.


Plug the CZeckpoint into an electrical outlet. Remove the protective cover from the probe tip and move the power switch from the OFF to the ON position. The RED (READY) light will flash for approximately 15 seconds as the probe tip is warmed up. At the conclusion of the warm-up period, the READY light will remain on and you will hear a short beep. The Czeckpoint is now ready for use.

To perform a test, place the probe tip squarely against the facet of the gemstone, using sufficient pressure for the spring-loaded metal tip to retract partially into it plastic housing. Press firmly and quickly, but do not press so hard that the probe tip retracts fully into the housing.

If the gemstone is a Diamond, the GREEN (DIAM) light will illuminate and you will hear a short beep.

If the gemstone is a CZ, the RED (READY) light may extinguish but will probably remain lit.

If the gemstones are some other type of Diamond simulant, the RED (READY) light will extinguish, and there will be no beep.

Please Note:

Moissanite stone could test as a Diamond. It is highly recommended that the Reliance be used in tandem with the Ceres Secure II ® Moissanite Detector whenever a “Diamond” reading is received.


The Czeckpoint´s advanced circuitry includes a feature that will automatically turn the unit off if it has been idle for approximately 90 seconds. If the instrument has turned itself off, simply move the power switch to the OFF position and then back to ON to restart.


The CZeckpoint incorporates a Warning Beeper indicating that the probe tip has come in contact with metal. Since gold and silver share Diamond´s high thermal conductivity, many diamond testers provide a Diamond reading when you are actually touching the metallic setting of the CZ jewelry.

For proper operation of the Warning Beeper, you must hold the piece of jewelry in one hand while touching the CZeckpoint ribbed contact plate with the thumb of your other hand. When contact is made with metal, the Dual XL will emit a two-tone signal, indicating that you must retest.


When you receive the Czeckpoint from your dealer, you MUST charge the batteries for 18 to 24 hours. You may, however, operate the unit using electrical power while the batteries are charging.

When the RED (READY) light seems especially dim, the unit´s audible tones are very faint. Or the Czeckpoint will not turn on while under battery power. The unit´s batteries will recharge. To recharge, simply insert the AC adaptor plug into the CZeckpoint charging jack and plug the adaptor into a suitable electrical outlet. Charge the batteries for 18 to 24 hours before using the product solely on battery power.


After two to three years, the Czeckpoint´s rechargeable nickel-cadmium battery pack will eventually lose its ability to recharge and will require replacement. The batteries will need replacement when the unit will not power up even when plugged into an electrical outlet.

Replacement battery packs are available from Ceres Electronics or from the dealer form that the product was purchased. Do not use any battery pack other than that specifically manufactured for this product use of improper batteries could cause damage to the product and may be a fire hazard, and will VOID the Limited Lifetime Warranty.


Test only clean gemstones, since body oil, dirt, and dust can produce incorrect readings. Make sure that the stone is completely dry after cleaning, as water and other liquids could cause improper readings.

For accurate operation, the Dual XL and the gems should be at room temperature (65 to 75F/18-24C).

Clean the Probe Tip Frequently It is recommended that the tip be cleaned during warm-up each time the unit is turned on, and after a few minutes of continual operation. The probe may be cleaned by scratching it vigorously against a piece of paper. Do not use coated or waxed paper and be careful to point the probe tip straight down at the paper.

The Czeckpoint will always test very small stones more accurately when operated from an electrical outlet rather than from batteries. If you must operate the unit using its rechargeable batteries, be sure that the batteries are fully charged as directed above.

Do not test the same stone repeatedly, especially a very small stone, since a Diamond that has been warmed by repeated tests will test as a simulant unless sufficient time is given for the stone to cool to room temperature.

You must have a functioning battery pack attached to the unit for it to operate, even when using the AC adaptor. The Czeckpoint will not operate without a rechargeable battery pack installed.

Always test with sufficient pressure to ensure solid contact between the probe and the gemstone. Tests must be made firmly and quickly, particularly on small stones. Apply pressure to the probe tip the moment that contact is made with the stone.

Always keep the protective cover on the probe tip when not using the instrument. Turn the unit off when it is not in use.


In the event that your CZeckpoint is not performing to your expectations, we strongly recommend calling Ceres Electronics Customer Service Department before returning it for repair. Many problems can be solved quickly over the phone, without the need to return the unit for service. Specifically, make sure you have cleaned the probe tip thoroughly before shipping, as this is most common cause of improper function


There are no user-serviceable parts in the unit. Do not take it apart, as there are areas on the circuit that when touched will give an uncomfortable electrical shock. Evidence of tampering also voids the Limited Lifetime Warranty.


Ceres Electronics Corporation warrants that this Ceres Dual XL will be free from defects in materials and workmanship for as long as you own it. This warranty extends only to the original purchaser of this instrument and does not include the probe tip and power adaptor, which are warranted for two (2) years.

In the event of a defect during the warranty period, Ceres Electronics Corporation should be notified and the purchaser should return the instrument to Ceres Electronics Corporation, freight prepaid, properly identified and with proof of purchase date. The sold obligation of Ceres Electronics Corporation, after reasonable opportunity to inspect the instrument, will be to repair or replace the defective instrument, or any part of the instrument that is proven to the satisfaction of Ceres Electronics Corporation to have been defective at the time of purchase, or that has become defective in normal use during the warranty period, at its option and at no charge to the purchaser.

The above warranty is void if the instrument has been service by anyone other than the Ceres Electronics Corporation or has been altered, abused, misused, or used for purposes other than those for which it was designed or used in a manner contrary to the instructions contained herein.

Ceres Electronics Corporation makes no warranties regarding the Ceres Dual XL other than those expressly contained herein. All other warranties of any kind whatsoever, whether expressed or implied, including warranties of merchantability or fitness for a particular purpose, are hereby disclaimed and are excluded by it. .

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