The cut is the most crucial factor in how beautiful a diamond is perceived. Regardless of color, clarity or carat, it is the cut that determines whether the stone sparkles intensely or looks lifeless. In this guide, we will go through what cut means, what grades are available, and how to choose the right one – whether you are looking at a round brilliant or one of our other grinding forms .

Cut describes how well a diamond is shaped, proportioned and polished. It is about precise angles, symmetry and balance between table, depth and facets. The aim is to maximise the light's journey through the stone, thereby creating:

• Brilliance: white light reflected out through the top
• Fire: play of colors of light in the rainbow spectrum
• Sparkle (scintillation): contrasts between light and dark zones

Diamonds were first cut to enhance their play of light as early as the 15th century. In 1919, Marcel Tolkowsky published a model for ideal proportions that still forms the basis for round brilliant-cut diamonds today.

1. Reflection: Some light bounces directly off the surface.
2. Refraction: Light is refracted inside the diamond and reflected between the facets.
3. Dispersion (fire): The light is split into different colors – the rainbow effect.

• Table: The upper flat surface where the light first hits.
• Crown: Inclined part from the table to the round bar.
• Rondist: The waist of the diamond.
• Pavilion: Lower part where the light is reflected upwards.
• Cullet: Small point or surface at the bottom.
• Depth: The height of the diamond from table to culet in relation to width.

At Diamant Banken, the exact dimensions of each stone are displayed in millimeters, as well as certificates with proportions in percentages and degrees.

Only round brilliant-cut diamonds receive an official cut grade in certificates. The IGI uses the term Ideal , while the GIA uses Excellent – ​​both indicate maximum brilliance.

We offer the following grinding grades:

• Ideal/Excellent: For those seeking the highest possible brilliance. Especially recommended for solitaire rings.
• Very Good: Close to ideal – slightly lower light rendering but still very beautiful.
• Good: Good brilliance, but noticeable compromises in light play.

See all round brilliants with Ideal or Excellent cut

Other shapes such as oval , emerald , cushion or pear do not receive an official cut grade. Here, cut is evaluated via:

• Depth % and Table %
• Symmetry and polish (found in the certificate)
• Length-to-width ratio – important for the shape to look balanced

See our overview of all grinding shapes – there you will find exact guidelines for ideal proportions.

Some round brilliants exhibit a perfect pattern of 8 hearts (from below) and 8 arrows (from above). These are called Hearts & Arrows and require extremely precise cutting.

Contact us if you are looking for a Hearts & Arrows diamond – we can often provide picture documentation and help you find the right one.

• Choose Ideal (IGI) or Excellent (GIA) for round brilliants
• Avoid grinding grades below Good – see the full range
• Use our guides to ensure symmetry and polish
• Explore settings that highlight the brilliance of the cut

A well-cut diamond makes all the difference – it maximizes the play of light, enhances clarity and creates the iconic sparkle that distinguishes an exclusive piece of jewelry.