Which diamond form has eight equal triangular sides?

Which diamond form has eight equal triangular sides?

• A. Open-pit mining
• B. Old European cut
• C. Octahedron
• D. Normal

Answer: (C)

Diamonds grow in distinct crystal forms, and the number and shape of their faces identify the form. An octahedron is a crystal form with eight triangular faces, and in a regular octahedron those faces are all congruent equilateral triangles. So you get eight equal triangular sides. This is a classic natural diamond habit because diamonds crystallize in the cubic system in a way that produces a symmetric octahedral shape, with four faces meeting at each vertex. The other options aren’t crystal forms with eight equal triangular faces: one is a mining method, another is a historical cut style that uses a different facet arrangement, and the last isn’t a recognized crystal form.

Diamonds grow in distinct crystal forms, and the number and shape of their faces identify the form. An octahedron is a crystal form with eight triangular faces, and in a regular octahedron those faces are all congruent equilateral triangles. So you get eight equal triangular sides. This is a classic natural diamond habit because diamonds crystallize in the cubic system in a way that produces a symmetric octahedral shape, with four faces meeting at each vertex. The other options aren’t crystal forms with eight equal triangular faces: one is a mining method, another is a historical cut style that uses a different facet arrangement, and the last isn’t a recognized crystal form.