| The most common diamond shapes: |
Every diamond is unique. Each reflects the story of its arduous journey from deep
inside the earth to a cherished object of adornment. Yet all diamonds share
certain features that allow us to compare and evaluate them. These features are
called the 4Cs.
Carat Weight: One carat equals 1/5 of a gram in weight. For diamonds under a
carat, each carat is divided into 100 points – similar to pennies in a dollar. 0.75ct. =
75 points, ½ ct. = 50 points
Clarity: The GIA Clarity Scale includes eleven clarity grades ranging from
Flawless to I3. Given that diamonds form under tremendous heat and pressure,
internal and external characteristics are common. These characteristics help
gemologists separate natural diamonds from synthetics and simulants, and
identify individual stones. There are two types of clarity characteristics: inclusions
and blemishes – the difference is based on their locations. Inclusions are
enclosed within a diamond while blemishes are confined to its surface.
Color: The GIA Color Scale extends from D (colorless) to Z (light yellow or
brown). Although many people think of gem quality diamonds as colorless, most
diamonds used in jewelry are nearly colorless with tints of yellow or brown. Color
grades are determined by comparing each diamond to a master set. Each letter
grade represents a range of color and is a measure of how noticeable the color is.
Cut: The GIA Cut Scale ranges from Excellent to Poor. GIA provides a cut quality
grade for standard round brilliant diamonds that fall in the GIA D-to-Z color
range. A polished diamond’s beauty lies in its complex relationship with light:
how light strikes the surface, how much enters the diamond, and how, and in
what form light returns to your eye. The result is a display of three attributes.
Brightness is the combination of all white light reflecting from the surface and
interior of a diamond. Fire is the colored flashes that can be seen in a diamond.
Scintillation describes the sparkle of light you see in a diamond, and the overall
pattern of bright and dark areas when you look at a diamond face-up. A polished
diamond’s proportions affect its light performance, which in turn affects its
beauty and overall appeal. Diamonds with good proportions optimize the
interaction with light, and have good brilliance, fire, and scintillation. The Design
(weight ratio, durability) and Craftsmanship (polish, symmetry) of a diamond
also affect its cut quality, and are considered in determining a diamond’s GIA
Cut Grade.
Fluorescence: Many diamonds emit a visible light when exposed to ultraviolet
radiation. Although fluorescence is not a factor in determining color or clarity
grades, a description of its strength and color is provided on GIA Reports for
identification purposes.
inside the earth to a cherished object of adornment. Yet all diamonds share
certain features that allow us to compare and evaluate them. These features are
called the 4Cs.
Carat Weight: One carat equals 1/5 of a gram in weight. For diamonds under a
carat, each carat is divided into 100 points – similar to pennies in a dollar. 0.75ct. =
75 points, ½ ct. = 50 points
Clarity: The GIA Clarity Scale includes eleven clarity grades ranging from
Flawless to I3. Given that diamonds form under tremendous heat and pressure,
internal and external characteristics are common. These characteristics help
gemologists separate natural diamonds from synthetics and simulants, and
identify individual stones. There are two types of clarity characteristics: inclusions
and blemishes – the difference is based on their locations. Inclusions are
enclosed within a diamond while blemishes are confined to its surface.
Color: The GIA Color Scale extends from D (colorless) to Z (light yellow or
brown). Although many people think of gem quality diamonds as colorless, most
diamonds used in jewelry are nearly colorless with tints of yellow or brown. Color
grades are determined by comparing each diamond to a master set. Each letter
grade represents a range of color and is a measure of how noticeable the color is.
Cut: The GIA Cut Scale ranges from Excellent to Poor. GIA provides a cut quality
grade for standard round brilliant diamonds that fall in the GIA D-to-Z color
range. A polished diamond’s beauty lies in its complex relationship with light:
how light strikes the surface, how much enters the diamond, and how, and in
what form light returns to your eye. The result is a display of three attributes.
Brightness is the combination of all white light reflecting from the surface and
interior of a diamond. Fire is the colored flashes that can be seen in a diamond.
Scintillation describes the sparkle of light you see in a diamond, and the overall
pattern of bright and dark areas when you look at a diamond face-up. A polished
diamond’s proportions affect its light performance, which in turn affects its
beauty and overall appeal. Diamonds with good proportions optimize the
interaction with light, and have good brilliance, fire, and scintillation. The Design
(weight ratio, durability) and Craftsmanship (polish, symmetry) of a diamond
also affect its cut quality, and are considered in determining a diamond’s GIA
Cut Grade.
Fluorescence: Many diamonds emit a visible light when exposed to ultraviolet
radiation. Although fluorescence is not a factor in determining color or clarity
grades, a description of its strength and color is provided on GIA Reports for
identification purposes.
| THE FOUR C'S According to the GIA: The World's Foremost Authority in Gemology |
| Email: lexi@jeweladvisor.com Phone: 817-271-1529 New York |
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