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When shopping for a diamond, whether for an engagement ring, earrings or pendant, a few important benchmarks should be taken into consideration:

 1/ The first and foremost is the cut of the diamond.

 With Round, Cushion, Emerald Cut, along with the many additional options of shapes available, a finely cut diamond will display more brilliance and fire than a diamond that was cut to save carat weight from the original crystal.


A diamond that is cut too deep or too shallow, regardless of size, will lack the potential for the balance of brilliant white light and spectral colors that are available to the beholder of an ideal cut diamond.

 Even diamonds of lower clarity grades and color will exhibit a better reflectivity as long as the proportions, polish and symmetry are given prominence. A cut grade such as the American Gem Society “Ideal” or the GIA “Excellent” grade will assure the wearer of this desired attribute.

 2/ The Second important criterion for choosing a diamond is the color grade.

The standard color grades range from colorless “D” to fancy intense yellow.

Selecting a diamond which ranges from “G” color, (rare white) through “I” (slightly tinted white) will offer a near 100% amount of white light to be reflected back to the observer with only a minuscule amount of the crystal’s natural body color impacting the brilliance of the Diamond.

The choice of a near colorless diamond allows for the beauty of the stone to shine through without the steep price increase for a “D” or absolute colorless diamond.

 3/ The third standard in choosing a diamond is the clarity grade.

 The grade of flawless is the top quality grade through “I3” or Imperfect 3.   A clarity grade of flawless means that under a 10 power magnification, no inclusions (clouds, pinpoints, crystal growth lines, etc.) are visible to the eye.

This grade might be desirable should the purchaser seek a diamond for investment purposes. However, for a beautiful wearable diamond, an above mid-point grade of anywhere from VS1 to SI1, (very slightly imperfect to Slightly imperfect) encompasses minor inclusions not usually visible to the naked eye which do not deter from the dynamics of a diamond’s brilliance.

Again, choosing a clarity grade VS-SI1, reduces the cost of the diamond without affecting the beauty of the diamond.

 A stunning diamond can be chosen with an emphasis on the first criteria and modest deductions in grading on the remaining two benchmarks, gaining a reduction in cost while achieving a gem of quality.

In summary, when shopping for a diamond the proportional cut being the primary category of importance with color and clarity following.

 Jeff Deleuse, Graduate & Certified Gemologist Appraiser from the Gemological Institute of America

ALL diamonds sold from Deleuse Jewelers are ethically sourced and 100% conflict-free from Kimberley certified diamond dealers. The gems used in our jewelry are also sourced from our industry wholesalers exclusively by the AGTA & AGS. We are members of the AGTA, AGS and GIA Certified Gemologist.

All gold used for manufacturing is purchased from our local refinery and 100% recycled. This has been our policy for 30 years.

55 Broadway, Fairfax, Ca 94930




Jeff Deleuse

  • B.A. Psychology
  • Advanced French Language, University of Nice, France
  • Stanford Continuing Studies
  • Graduate Gemologist, Certified Appraiser 

Janet Deleuse

  • B.S.  Molecular Biology
  •  Stanford Continuing Studies, Art History and Literature
  • Saul Bell International Jewelry Award Judge, 2015
  • Past Board Marin Advocates for Children, 2014
  • Contributing Writer and Featured Designer in Jane Merrill's book"I Love Those Earrings" 2014
  • Audio Contributor to “Cartier & America” Exhibit at the Legion of Honor, San Francisco, 2010-2011
  • Janet Deleuse Couture Featured in Britex  Newsletter, San Francisco, 2012
  • "Fashion & Impressionism" research paper written in Spring 2011; for exhibit
  • Cartier Achievement Award presented June 2009
  • Women's Jewelry Association Award January 2009
  • Contributing Writer for LUXX International Jewelry Magazine, 2009-2010


  • Graduate Gemologists
  • Past Members of the American Gem Trade Association
  • Past American Gem Society
  • Jewelers Of America
  • Women's Jewelry Association
  • Contemporary Jewelers Design Group