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Often diamond beauty could be described in terms of the following phenomena:

  • Brightness

  • Brilliance

  • Scintillation

  • Fire

Quantitative description of these phenomena is what we call diamond beauty metrics.

Fire metrics

Fire is an ability of a gem to produce colored flashes seen usually under point light source conditions. Fire is probably the most appealing optical effect in a diamond.

Quantitative description of fire involves frequency (number) of colored flashes, their intensity and colorfulness, spatial and temporal distribution.

Read more on Fire and other optical performance in our Australian Gemologist article "How diamond performance attributes: Brilliance, Scintillation and Fire depend on human vision features":

Fire metrics in Cutwise

We arranged Fire metrics in the following high-level categories:

  • Fire Integral Metric (answers to the question "which stone has better Fire ability")
  • Fire Intensity Metric (answers to the question "which stone has more Fire")
  • Fire Uniformity Metric (answers to the question "which stone has better distributed Fire")

All of these metrics could be measured in stereo (binocular) and mono conditions. Stereo metrics are used as default for display, stones filtration and sorting.

Beside the absolute values of Fire metrics we calculate relative metrics of "Fire per area" which describe the cut quality and abstract from the stone size.

Absolute metrics are normalized to MSSRBC13 as an excellent round reference sample.

Fire Intensity metrics are measured in Dynamic as well as Static condition. Fire Intensity Dynamic shows amount of fire stone shows during small tilting moves. Fire Intensity Static shows mean of fire amount in random static stone position.


Fire metrics display on a stone page

Fire metrics report (for a stone list)

To get to a fire metrics report you need to

  • log in to Cutwise, you could use login using Facebook
  • create a new search and save it (in the left sidebar), you could add selected stones to your wish list to get report for them only
  • click "Optical metrics report" link for your saved search


Fire metrics report contains the following data types

  1. Bar charts for fire metrics (integral, intensity and uniformity charts)
  2. Stacked bar charts for histograms (flashes size and flashes duration histograms)
  3. Fire properties distribution chart (flashes average size and flashes average duration)

Fire / Brilliance scatter chart contains Fire Stereo (Absolute), Brilliance and Optical Performance metrics. 

Fire intensity chart contains four fire intensity metrics (Dynamic Stereo, Dynamic Mono, Static Stereo and Static Mono) showing amount of fire in different viewing conditions. Fire integral and fire intensity charts has the switch between absolute metric and relative metrics (per carat and per area).

Fire uniformity chart contains spatial uniformity, temporal uniformity and integral uniformity metrics.

Fire flashes histograms contains two charts, one histogram showing flashes size distribution and the other one - flashes duration distribution. You could switch between measurement units - number of flashes, flashes area and flashes value (area * intensity). It is possible to switch between absolute quantities and relative quantities in percents.

Fire properties distribution scatter chart shows each stone in axes of average relative flashes size and duration. Small flashes - left side and large flashes - right side. Fast flashes - bottom side and slow flashes top - side. Shapes marked with color by default.

Topmost controls of a fire metrics report contains

  • a switch between All stones in the current list / new stones only / stones added to wish list
  • a sorting switch, sorting applies to all the charts
  • saved searches panel in the right sidebar containing the option to return to a general listing.

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