Diamonds have been treasured for centuries due to their rarity, durability, and beauty. Their sparkle comes from facets that reflect light internally and externally. Diamonds are graded on the 4 Cs - color, clarity, cut, and carat weight. Higher grades mean fewer inclusions, closer to colorless color, ideal cutting proportions, and larger size. Proper cleaning maintains a diamond's brilliance. Synthetic diamonds and simulants like cubic zirconia are available but have distinguishing characteristics. Understanding these basics empowers consumers.

1. Diamonds: Beauty and Brawn
Carl Wozniak
Graduate Gemologist (GIA)
Northern Michigan
University

2. The allure of diamonds
• The world’s love of diamonds
started in India.
• Romans set uncut diamonds in
jewelry
• By the 1400s, diamonds had
become fashionable in Europe.
Roman ring, 4 A.D.

3. Why the allure?
 Diamonds are
cherished because:
 They are rare
 They are durable
 They are beautiful
 They have value
 They are expensive to
mine and cut

4. Cutting
 Diamonds are
extremely hard.
 In order to cut
them, you have to
use other
diamonds.
Rough diamond

6. Diamond
anatomy
A round brilliant cut diamond
has either 57 or 58 facets.

7. What makes diamonds
sparkle?
 A polished diamond’s beauty lies in a
complex relationship with the light
around it.
 Facets on the stone reflect light
externally and internally.

8. What makes diamonds
sparkle?
 We see this interplay between light and
the diamond in three qualities
 Brilliance- the degree to which light from
within the stone returns to our eye
 Fire- the play of colors from the refraction
of light within the stone
 Scintillation- the bits of light that flash as
the stone is moved

9. Brilliance
In brilliant stones, much of the light that enters leaves
through the crown. Less brilliant stones result when
light leaks out the pavilion.

10. Fire
Fire, also known as
dispersion, is the color play
within a diamond caused by
refraction of light in the
stone.

11. Scintillation
Scintillation is caused by
light reflecting off the
stone’s facets.

12. Grading diamonds
 Why grade diamonds?
Diamond grading:
 Makes it possible to
discuss diamonds
simply and
concisely;
 Helps you compare
stones;
 Helps identify
quality.

13. Grading diamonds
 The 4 “C’s”
 Color
 Clarity
 Cut
 Carat weight

14. Color
 While there are fancy colored diamonds that can be
extremely expensive, typical diamonds increase in
value as they get closer to colorless.
 The currently used grading scale was developed by the
Gemological Institute of America
 A, B, C were not used to prevent confusion with
existing scales.
Hope Diamond
45.52 ct., VS-1,
Fancy deep
grayish blue

15. Rule of thumb
 Colorless face up and face down
 D, E, F
 Colorless face up, nearly colorless face down
 G, H, I, J
 Faint yellow face up, faint yellow face down
 K, L, M
 Very light yellow face up and face down
 N, O, P, Q, R
 Light yellow (substantial) color face up or
down
 S, T, U, V, W, X, Y, Z

16. Color
 Color is very difficult to judge in
mounted stones
 Proper lighting is essential

17. Clarity
 Most diamonds come with
some amount of “junk”
inside them. We call these
inclusions.
 Scratches and other surface
imperfections are called
blemishes.
 Before the 1950s people in
the diamond industry had
no way to accurately
describe a diamond’s
features so that everyone
understood them in the
same way.

18. Clarity
 The GIA’s diamond grading system was
developed in 1953 to give professionals
a way to evaluate diamonds and
communicate quality to others.

19. Clarity
 Five clarity factors that determine the grade of
a diamond
 Size of inclusion
 Number of inclusions
 Position of inclusions
 Nature of inclusions
 Color or relief of inclusions
 The clarity grade is not based on the sum of
everything in the stone, but is based on the
largest and most visible characteristics.

20. Typical Inclusions
Clouds
Feathers
Crystals
Needles
Pin points

21. Clarity Grades
 Flawless (F) stones are exceedingly
rare and never worn.
Millenium Star,
203.04 ct., D, Flawless
Flawless stones have no visible
inclusions under 10 X
magnification, and there are no
blemishes on the stone’s
surface.

22. Clarity Grades
 Internally Flawless (IF) diamonds have
the potential to become flawless stones.
Internally flawless stones have
no visible inclusions under 10 X
magnification, but there are
blemishes on the stone’s
surface.

23. Clarity Grades
 Very Very Slightly (VVS) included
diamonds
Contain minute inclusions that are
extremely or very difficult for a
skilled grader to see under 10 X.
•VVS1= extremely difficult to see
face up (one or two pin points)
•VVS2= somewhat easy to see

24. Clarity Grades
 Very Slightly (VS) included diamonds
Contain minor inclusions that are
difficult to easy for a skilled
grader to see under 10 X.
•VS1= difficult to see inclusions
•VS2= somewhat easy to see
•Typically small crystals or
feathers near the edge.

25. Clarity Grades
 Slightly Included (SI) diamonds
Contain noticeable inclusions
that are easy or very easy for a
skilled grader to see under 10 X.
•SI1= easy to see inclusions
•SI2= very easy to see. Eye
visible.
•Typically crystals, feathers or
clouds centrally located.

26. Clarity Grades
 Included (I) diamonds
Contain obvious inclusions to a
skilled grader under 10 X.
•I1= quite visible inclusions
•I2= easily visible
•I3= extremely visible. Affects the
stone’s durability.
I-2
I-3

27. Cut
 Diamonds can be cut
in many different
shapes, but this is
not all we mean by
“cut.”
 Cut refers to not only
the shape of the
diamonds, but its
proportions and finish,
factors which
determine the sparkle
of the diamond.

28. Cut
 Round brilliant cut diamonds have been
studied the most.
 They are the most common
 The proportions are relatively consistent

29. Cut

30. Cut
Misalignment of
facets, misshapen
facets, and pointing
problems go hand-in-
hand. Where you find
one, you’ll usually
find the others.

31. Carat weight
 Diamonds weight
is measured in
carats.
 1 ct. = 1/5 gm.
 1/100 ct. = 1 point

32. Carat weight
 Rule of Thumb 1
 All other things
being equal, the
bigger the stone,
the more
expensive it is.

33. Carat weight
 Rule of Thumb 2
 Cost jumps
dramatically at
“magic sizes.”

34. The care and feeding of
diamonds
 Diamonds have a high
affinity for grease. Rough
diamonds are actually
sorted using grease
tables.
 Grease changes the
refractive index of the
stone, causing light to leak
out the pavilion.

35. The care and feeding of
diamonds
 Use an old toothbrush and soapy water
to clean under the stone.
•Can also use
ultrasound or steam
•Keep gold jewelry
away from chlorine
bleach.

36. Synthetic diamonds
 Synthetic diamonds are becoming more
common, but they are usually small stones,
yellowish stones.
Diamonds are made under
temperatures of about
2,200º F and 50,000
atmospheres.

37. Synthetic diamonds
Cremated remains can be made
into diamond.

38. Common Diamond Simulants
 Cubic Zirconium (Zircon Oxide)
 CZ has slightly less brilliance or sparkle
than a diamond and more fire or flashes of
color
CZ also comes
in many colors.

39. Common Diamond Simulants
 Telling CZ from diamond
 About 75% heavier than diamond
 CZ is softer, you see this in abraded facet
junctions
 Orange pavilion flash
 Usually flawless
 Many colors
 Thermal conductivity

40. Common Diamond Simulants
 Moissanite- Silicon
carbide
 Has inclusions and
color differences
 Similar thermal
conductivity
 Very hard
 Slightly lighter than
diamond
Moissanite has a
lot more fire than
diamond.

41. Common Diamond Simulants
 Moissanite- Silicon
carbide
 But, moissanite is
strongly doubly
refractive

42. A little knowledge will make you a
better consumer.
 You’re invited to
clean and
examine your
own stones.