Polish lines

Polish Lines and Marks: tiny parallel lines or surface clouding left by irregular polishing or excessive heating during polishing, respectively.
Rough Girdle: a grainy or pitted girdle surface usually caused by poor workmanship.

Polish Lines (PL)
Fine parallel surface groves resulting from the polishing process.
Polish Marks (PM)
Also known as "Wheel Marks," whitish film on the surface of a facet caused by excessive heat during polishing.

Polish Lines
Polish Lines are Lines that are left on the surface of the stone by irregular Polishing.
Pit ...

Polish Lines Faint surface lines visible either as a result of imperfect polishing, or of grain lines in the diamond.
Princess A square or near square (oblong) diamond, which has been facetted in a brilliant cut style rather than a step cut.

Polish lines
White lines that appear on a diamond due to polishing. Caused usually because of uneven surface of a diamond.
Polish mark ...

For instance, if polished too quickly, polish lines might appear as minute scratches on a facet's surface. It is even possible for the cutter to burn the diamond.

On the contrary, when these flaws / marks occur on the surface, they are known as blemishes and the most common types of blemishes include Polish lines, Naturals, Scratches, Nicks, Pits, transparent stress lines that appear on a diamond's surface, ...

Blemishes are the surface defects of a diamond such as chips, nicks, polish lines, grain boundaries etc. However, for grading purposes all flaws are called inclusions.

Nicks, Scratches and Abrasions
Natural: A portion of the diamond's rough or original surface left on a polished stone, usually at the girdle.
Polish Lines: Fine, transparent or white parallel grooves and ridges left by polishing.

Cut grade also encompasses attributes such as polish lines, pits, misalignment of facets, off-center table, naturals, extra facets, wavy girdle (perimeter), ...

See also: Polish, Diamond, Clarity, Stone, Eye