The read-through test is reliable for which stones?

• A. Well-proportioned round brilliant cut stones
• B. Very poorly proportioned round stones
• C. Colored stones
• D. Fragmented stones

Answer: (A)

The read-through test relies on how light travels straight through a gemstone from one surface to the opposite side. It works best when the stone has near-ideal symmetry and high clarity, because the light path is smooth and the view through the stone is clean. Well-proportioned round brilliant cut stones provide that uniform light path due to their precise geometry and evenly distributed facets, so you can read through them clearly and consistently. When a stone is poorly proportioned, its irregular facet angles disrupt light return, making the through-view distorted and unreliable. Colored stones often reduce transparency or alter what you’d see through the stone, and fragmented stones have cracks or fractures that scatter light, both of which disrupt a clean read-through.