What do trigons indicate on a diamond?

What do trigons indicate on a diamond?

• A. A cubic plane
• B. An octahedral plane
• C. A dodecahedral plane
• D. A tetrahedral plane

Answer: (B)

Trigons are triangular markings that reveal the orientation of the diamond’s crystal planes. In a diamond’s cubic lattice, the most influential planes are the octahedral {111} planes. When surface features align with or intersect those planes, triangular markings called trigons form. So the presence of trigons indicates an octahedral plane on the diamond. They would not indicate cubic {100}, dodecahedral, or tetrahedral planes, which would produce different patterns or none of these triangular marks.

Trigons are triangular markings that reveal the orientation of the diamond’s crystal planes. In a diamond’s cubic lattice, the most influential planes are the octahedral {111} planes. When surface features align with or intersect those planes, triangular markings called trigons form. So the presence of trigons indicates an octahedral plane on the diamond. They would not indicate cubic {100}, dodecahedral, or tetrahedral planes, which would produce different patterns or none of these triangular marks.