- 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.
- 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.)
- Lower Girdle Facet - Triangular facets just below the girdle.
- Luster - the quality of shining by reflecting light from the surface of a diamond.
- Irradiated Diamond - a diamond exposed to radiation to alter its color to a fancy color.