Three viewing surfaces
The weathered exterior may differ sharply from the interior. A window exposes a limited spot; a cut face reveals a broader plane but not the whole volume. Color veins and fractures can change direction beyond what is visible.

Describe before predicting
Record skin texture, exposed color, translucency under controlled light, visible fractures and scale. Avoid turning those observations into certainty about yield. Even experienced cutting decisions carry material risk.

Photography adds another layer
Wet surfaces, backlighting and high contrast can intensify color. Ask whether the rough is wet or dry and request multiple orientations with a scale reference. Photographs support questions; they do not remove uncertainty.

Research basis
Independently written from public information supplied by GIA, Smithsonian and The Metropolitan Museum of Art. GIA · Smithsonian · The Met