Outline a basic field workflow for diamond identification.

• A. Use X-ray diffraction first, then oil test.
• B. Visual inspection with loupe, assess inclusions, measure with calipers, test refractive index, test fluorescence, perform a quick thermal conductivity test, and compare results to expectations.
• C. Only measure refractive index and ignore others.
• D. Perform color grading before any physical inspection.

Answer: (B)

In field identification, you build confidence by using a practical sequence of quick, non-destructive checks that together point to diamond. Start with a careful visual inspection using a 10x loupe to note surface quality, facet workmanship, and, most importantly, inclusions. The pattern, type, and presence of inclusions can distinguish natural diamonds from many simulants, since many imitations lack the telltale internal features or show very different inclusion textures. Then measure the stone with calipers to capture its dimensions, which helps you estimate size and check whether proportions look consistent with its reported weight. Next, determine the refractive index with a handheld refractometer; diamond’s RI is around 2.417, which is a strong differentiator from most imitations that have notably lower or higher RI values. Fluorescence under UV light adds another layer: natural diamonds often show blue fluorescence, while many simulants fluoresce differently or not at all, providing a useful clue when combined with other data. A quick thermal conductivity test serves as a practical field screen because diamond conducts heat rapidly relative to common substitutes like cubic zirconia or glass. Finally, you compare all the gathered results to known diamond properties and expectations, using the combined evidence to decide whether lab confirmation is warranted. This approach is preferable in the field because it uses accessible tools in a logical sequence and avoids relying on any single test, which can be misleading or inconclusive on its own.