• Laser Drill Hole – A hole made in a diamond by laser drilling.

This technique is used to reach a black pique in order to bleach it (with acid) and improve the look and clarity of the stone. However, as this is a treatment, it materially (negatively) impacts the value of the diamonds. A jeweler should always disclose to you that a diamond has been laser drilled prior to your purchasing. Additionally, any paperwork on the diamond should also reflect this.

  • Laser Inscription – labs inscribe the grading report or certificate number on a diamond’s girdle.

Using a laser, labs can inscribe the grading report or certificate number (or client reference) on a diamond’s girdle. This has no impact on the diamond’s value, but makes it easier to identify the diamond.

  • Lizard Skin – wavy area on the surface of the diamond (that looks like lizard skin!)
  • Loupe – a small, handheld magnifying glass used to view diamonds.

A 10x loupe is standard, but other powers are available (14x, 20x, etc.). Gemologists use this to closely examine stones and establish key characteristics such as color grade and clarity grade. While two diamonds may look identical to the naked eye, they will likely have very different color and clarity grades (for example) upon closer inspection. This in turn has a big impact on the value of the stones. 

  • Lower Girdle Facet Triangular facets just below the girdle.
  • Luster – the quality of shining by reflecting light from the surface of a diamond.