A well shaped, transparent, octahedral diamond crystal with sharp, square edges?

A well shaped, transparent, octahedral diamond crystal with sharp, square edges?

• A. Crystal
• B. Crystaline
• C. Glide Plane
• D. Glassie

Answer: (D)

Crystals have a regular, repeating arrangement of atoms and well-defined faces. A diamond that is well shaped, transparent, and forms an octahedron with sharp edges shows this orderly internal structure and clear crystal habit, so the best descriptor is that it is a crystal. The other terms don’t fit: the form that looks like a misspelled version of crystalline isn’t standard terminology; a glide plane is a symmetry element, not a name for the object itself; and a word implying glassy material would describe a non-crystalline substance, which doesn’t match a diamond’s ordered lattice.

Crystals have a regular, repeating arrangement of atoms and well-defined faces. A diamond that is well shaped, transparent, and forms an octahedron with sharp edges shows this orderly internal structure and clear crystal habit, so the best descriptor is that it is a crystal. The other terms don’t fit: the form that looks like a misspelled version of crystalline isn’t standard terminology; a glide plane is a symmetry element, not a name for the object itself; and a word implying glassy material would describe a non-crystalline substance, which doesn’t match a diamond’s ordered lattice.