For a buyer choosing between these two instruments, moissanite screening is the decisive question. The Presidium Diamond Mate A is a thermal screening tester; the GemOro UltraTester 3+ is designed to help separate diamond, moissanite and white sapphire.
Understand the Diamond Mate’s limit
Presidium’s handbook explicitly states that the Diamond Mate cannot distinguish diamond from moissanite. A diamond indication therefore leaves an important identification question unresolved.
That does not make it useless. It makes it a tool with a defined role in a larger inspection process. If you already have a suitable follow-up method, a thermal screening result can still be informative.
If you expect one purchase to address the diamond-versus-moissanite question, the Diamond Mate A alone is not the right stopping point.
Why consider the UltraTester 3+?
The UltraTester’s broader stated screening purpose makes it the more relevant shortlist choice when those three materials are your main concern. Its value depends on using it within the documented conditions and interpreting its signals correctly.
We have not run a controlled comparison of false readings or detection performance. This recommendation follows the instruments’ documented purposes, not a claim that one has won a laboratory test.
Compare ownership as well as capability
Check the exact version, power accessories, probe support and available instructions. A tester that cannot be kept ready and used consistently will contribute less than its feature list suggests.
Ask the seller what happens if the probe is damaged or the instrument needs assessment. Keep the invoice and model details with your inspection records.
Before using either tester on unfamiliar jewelry, learn its controls and practise the documented procedure with suitable identified reference material.
Our recommendation
Shortlist the UltraTester 3+ if separating diamond from moissanite is a key purchase requirement. Consider the Diamond Mate A when you deliberately want a simpler thermal screening stage and understand the necessary follow-up.
Neither instrument should be purchased on the assumption that a routine “diamond” result establishes natural origin, a clarity grade or a resale value. Decide which question you need answered before comparing prices.
Explore the relevant products
- Presidium Diamond Mate A PDMT-A Diamond Screening Tester
- GemOro UltraTester 3+ Diamond, Moissanite & White Sapphire Tester
Check the exact model, seller, package contents and current offer on the linked product page before ordering.
Sources and further reading
- Presidium Diamond Mate A/C specifications
- Presidium-authored Diamond Mate handbook
- GemOro UltraTester 3+ manual
Explore more Gold Kings buying guides.
As an Amazon Associate I earn from qualifying purchases. The product pages linked in this article contain Amazon affiliate links. This guide is based on published specifications and practical buying considerations, not a controlled hands-on product test.