The perfectly shaped octahedral rough is described as what?

• A. Common
• B. Unstable
• C. Rare
• D. Average

Answer: (C)

Diamonds naturally form in a variety of crystal shapes, and the octahedron is a well-known habit for rough diamond crystals. When a rough is described as perfectly shaped octahedral, it means the crystal has smooth, evenly developed faces and sharp, unblemished edges. Such pristine octahedral crystals are not common because growth conditions, internal inclusions, and later weathering or damage often disturb the faces or edges. Because finding a clean, undamaged octahedron is unusual, it is described as rare. This rarity also makes such octahedral rough especially desirable for cutting, since it can yield good material with less waste.