At 10X magnification, which is a long, thin crystal that looks like a tiny rod?

At 10X magnification, which is a long, thin crystal that looks like a tiny rod?

• A. Normal color range
• B. Needle (Ndl)
• C. Nick (Nk)
• D. Octahedron

Answer: (B)

Needle inclusions are elongated crystals that appear as slender rods inside a diamond when you view it at 10X magnification. The description “a long, thin crystal that looks like a tiny rod” matches this clearly, since a needle stays narrow and rod-like as it runs through the crystal. The other options describe different things: a nick is a small surface chip, not an internal rod; an octahedron is a common diamond crystal form but not a long rod-shaped inclusion; and normal color range relates to color, not internal crystal shape. So the rod-like crystal seen at 10X is a needle inclusion.

Needle inclusions are elongated crystals that appear as slender rods inside a diamond when you view it at 10X magnification. The description “a long, thin crystal that looks like a tiny rod” matches this clearly, since a needle stays narrow and rod-like as it runs through the crystal. The other options describe different things: a nick is a small surface chip, not an internal rod; an octahedron is a common diamond crystal form but not a long rod-shaped inclusion; and normal color range relates to color, not internal crystal shape. So the rod-like crystal seen at 10X is a needle inclusion.