The Carat Standard

IGI report LG783622611

1.51 ct Marquise Laboratory-Grown Diamond

89/100 · Refined

A strong candidate on paper; confirm its light pattern in imagery.

What reads well

  • A 2.09:1 length-to-width ratio sits in the classic marquise range.
  • Face-up spread (12.28 × 5.88 mm) is typical or better for a 1.51 ct marquise.
  • F color is in the colorless range.
  • VVS2 clarity: inclusions are not a practical visual factor.
  • No fluorescence: no haze risk to weigh.

What deserves a closer look

  • A 64.5% depth is on the deep side for a marquise; deeper pavilions are associated with a stronger bow-tie and hidden weight.
  • Screening only: for this marquise, check images or video of the exact stone for the bow-tie and whether the two points line up end to end.
  • Treatment status is not stated on the report. For a laboratory-grown diamond, ask whether it is as-grown or post-growth treated.

The reading, field by field

Table · Ideal
At 59%, the table sits within the typical 53–63% range for a marquise, balancing brightness with fire.
Total depth · Closer look
64.5% is deeper than typical for a marquise (58–64%). Extra depth holds weight below the girdle, so the stone can face up smaller than its carat weight suggests and may show a stronger bow-tie.
Length-to-width · Ideal
A 2.09:1 outline is within the classic 1.85–2.2:1 range for a marquise.
Polish · Ideal
Excellent polish is the top finish grade — facets are cleanly executed with nothing that would soften sparkle.
Symmetry · Favorable
Very Good symmetry is a fine result; the difference from Excellent is rarely visible without magnification.
Girdle · Ideal
Medium To Slightly Thick (Faceted): a durable girdle thickness that doesn't hide meaningful weight.
Culet · Ideal
Pointed: no visible culet facet when viewed face-up.
Color · Ideal
F is in the colorless range and faces up white in any metal.
Clarity · Ideal
VVS2: inclusions, if any, are only visible under magnification.
Fluorescence · Ideal
None: no meaningful effect on appearance.

What to check on the exact stone

  • With 64.5% depth, does this stone face up smaller than a typical 1.51 ct marquise?
  • In a face-up video, does the bow-tie flicker as the stone tilts, or stay a fixed dark band across the center?
  • Will the ring setting use protective V-tip prongs or a bezel to safeguard the two delicate points?
  • Can you show me the inscribed report number under a loupe before it is set?

Report facts

Origin
Laboratory-grown
Carat
1.51 ct
Shape
Marquise
Cut grade
Not given for this shape
Color
F
Clarity
VVS2
Measurements
12.28 × 5.88 × 3.79 mm
Table
59%
Total depth
64.5%
Crown angle
Not given for this shape
Pavilion angle
Not given for this shape
Polish
Excellent
Symmetry
Very Good
Girdle
Medium to slightly thick (faceted)
Culet
Pointed
Fluorescence
None

About The Carat Standard Score

How The Carat Standard reads a report