Skip to primary navigationSkip to main contentSkip to footer
  • (781) 769-5470 (781) 769-6644
    1135 Washington St.
    Norwood, MA 02062
  • Toggle Search Menu
Keegan's Jewelers logo
  • Toggle Search Menu
  • Toggle My Account Menu
  • Toggle My Wishlist
  • Toggle Shopping Cart Menu
  • Engagement
    Engagement Rings
    Diamond Engagement RingsLoose Diamond SearchChoosing The Right SettingBuild Your Wedding BandDiamond Education
    Men's Wedding Bands
    Men's Diamond Wedding BandsMen's Gold Wedding BandsAlternative Wedding Bands
    Women's Wedding Bands
    Women's Diamond Wedding BandsWomen's Plainum Wedding BandsWomen's Gold Wedding Bands
    Create Your Own
    Create Your Own

    Explore All Engagement
  • Designers
    Allison KaufmanBering TimeCarla CorporationChatham
    CitizenGems OneKeegan's CustomLeStage
    Malo BandsMarathonOstbyePre-Owned Omega
    Pre-Owned RolexRembrandt CharmsSeiko

    Designers
  • Jewelry
    Rings
    Diamond RingsGold RingsCladdagh RingsColored Stone RingsPearl RingsSilver RingsMen's Gold RingsMen's Claddagh Rings
    Chains
    Gold ChainsSilver Chains
    Earrings
    Diamond EarringsGold EarringsColored Stone EarringsPearl EarringsSilver Earrings
    Necklaces
    Diamond NecklacesGold NecklacesColored Stone NecklacesPearl NecklacesSilver Necklaces
    Pendants and Charms
    Diamond PendantsGold Pendants and CharmsColored Stone PendantsPearl PendantsSilver Charms
    Bracelets
    Diamond BraceletsGold BraceletsColored Stone BraceletsPearl BraceletsSilver Bracelets
    Special Collections
    Convertible JewelryCape Cod JewelryReligious JewelryMedical JewelryChildren's Jewelry
    Create Your Own
    Create Your Own

    Explore All Jewelry
  • Watches
    Pre-Owned Rolex
    Pre-Owned Rolex
    Bering Time
    Bering Time
    Pre-Owned Omega
    Pre-Owned Omega
    Citizen
    Citizen
    Seiko
    Seiko
    All Watches
    All Watches

    Explore All Watches
  • New Arrivals
    • Seiko Watches
  • Services
  • Our Store
    About Us
    About Us
    Testimonials
    Testimonials
    Store Policies
    Store Policies
    Appointments
    Appointments

    Explore All Our Store
  • Contact Us
  1. Home
  2. Education
  3. Diamonds

Learn About Diamonds

The Four Cs of Diamonds:
Our Four C's of Diamonds guide can help you decide on the most important factors when shopping for a diamond. The Four C's of diamonds are known as Carat Weight, Cut, Color and Clarity.

Diamond Carat Weight

The word carat derives from the word carob, a Mediterranean seed, which has an extremely consistent weight for measuring. The greater the carat weight, the rarer, and more valuable the diamond becomes. Five metric carats weighs exactly 1 gram.

Some people want the largest diamond possible. If size is a priority, we at Keegan's Jewelers can help you classify the proper cut, color and clarity to fit your budget economically, and fit your jewelry beautifully. Many of our engagement rings can fit diamonds up to five carats or more, but each ring has different size constraints based on its size and the type of setting. Prong settings can be manipulated to fit virtually any size diamond, but tension-set diamonds and bezel set diamonds have more limitations on size.

  • Dime for size comparison
    17.9 MM
  • Round diamond, 0.10 carat (3.0mm diameter)
    0.10 CT
    (3.0 MM)
  • Round diamond, 0.15 carat (3.4mm diameter)
    0.15 CT
    (3.4 MM)
  • Round diamond, 0.20 carat (3.8mm diameter)
    0.20 CT
    (3.8 MM)
  • Round diamond, 0.25 carat (4.1mm diameter)
    0.25 CT
    (4.1 MM)
  • Round diamond, 0.5 carat (5.1mm diameter)
    0.5 CT
    (5.1 MM)
  • Round diamond, 0.75 carat (5.8mm diameter)
    0.75 CT
    (5.8 MM)
  • Round diamond, 1 carat (6.4mm diameter)
    1.0 CT
    (6.4 MM)
  • Round diamond, 1.25 carat (6.9mm diameter)
    1.25 CT
    (6.9 MM)
  • Round diamond, 1.5 carat (7.4mm diameter)
    1.5 CT
    (7.4 MM)
  • Round diamond, 1.75 carat (7.8mm diameter)
    1.75 CT
    (7.8 MM)
  • Round diamond, 2 carat (8.1mm diameter)
    2.0 CT
    (8.1 MM)
  • Round diamond, 2.5 carat (8.8mm diameter)
    2.5 CT
    (8.8 MM)
  • Round diamond, 3 carat (9.4mm diameter)
    3.0 CT
    (9.4 MM)
  • Round diamond, 3.5 carat (9.8mm diameter)
    3.5 CT
    (9.8 MM)
  • Round diamond, 4 carat (10.2mm diameter)
    4.0 CT
    (10.2 MM)
  • Round diamond, 5 carat (11.0mm diameter)
    5.0 CT
    (11.0 MM)
  • Round diamond, 6 carat (11.8mm diameter)
    6.0 CT
    (11.8 MM)
  • Round diamond, 7 carat (12.4mm diameter)
    7.0 CT
    (12.4 MM)
  • Round diamond, 8 carat (13.0mm diameter)
    8.0 CT
    (13.0 MM)
  • Round diamond, 9 carat (13.5mm diameter)
    9.0 CT
    (13.5 MM)
  • Round diamond, 10 carat (14.0mm diameter)
    10.0 CT
    (14.0 MM)
  • Round diamond, 12.5 carat (14.5mm diameter)
    12.5 CT
    (14.5 MM)
  • Round diamond, 15 carat (16.0mm diameter)
    15.0 CT
    (16.0 MM)

Diamond Cut

The true definition of cut is the quality of the proportions and symmetry of the diamond. Your diamond's proportions make a vast difference on how brightly your diamond shines. An 'ideal cut' diamond is one that allows the maximum amount of light to return through the top of the diamond, which takes into consideration the depth, table size, crown height and angle, girdle thickness and more. Our diamond professionals will be happy to assist you in selecting the best diamond cut.

After a rough diamond is mined, it is evaluated to determine its best possible cut, in order to maintain the maximum clarity, color, and carat weight. The term 'cut' is often confused with diamond 'shape', such as round brilliant or princess cut.

Diamond anatomy

Ideal

This is the rarest cut grade and reflects the most light.

Excellent

This cut grade reflects a high level of craftsmanship and light performance.

Very Good

This cut grade reflects nearly as much light as an Excellent cut grade, but for a lower price.

Good

This cut grade reflects most of the light that enters the diamond, but not as much as a Very Good cut grade.

Fair

This cut grade may appear dull or even glassy, and is very inexpensive.

Poor

This cut grade is not carried by Keegan's Jewelers and is typically not recommended.

Diamond Color

Color is one of the more noticeable attributes of a diamond and has a heavy impact on the price of the stone. Diamonds range from colorless to yellow or light brown, and are sometimes found in a spectrum of fancy colors, including yellow, blue, and even red diamonds. The less color, the rarer the diamond. After 'Z' on the color scale, diamonds become fancy yellow, which cost more because of their rarity.

F
E
D
F color diamond
E color diamond
D color diamond

Colorless

J
I
H
G
J color diamond
I color diamond
H color diamond
G color diamond

Near Colorless

Z-N
M-K
L color diamond
K color diamond

Noticeable Color

Z-N
M-K
J
I
H
G
F
E
D
L color diamond
K color diamond
J color diamond
I color diamond
H color diamond
G color diamond
F color diamond
E color diamond
D color diamond

Noticeable Color

Near Colorless

Colorless

Diamond Clarity

Diamonds are composed of mostly carbon. During the heating process, other elements become trapped inside, giving each diamond its own unique fingerprint. These inclusions help identify the clarity of your diamond. All diamonds are viewed through a 10x magnification lens by diamond graders.

Close up of inclusions in a diamond

(F) Flawless

No inclusions or blemishes are visible to a skilled grader.

(IF) Internally Flawless

No inclusions and only blemishes are visible to a skilled grader.

(VVS1-2) Very Very Slightly Included

Inclusions are difficult for a skilled grader to see.

(VS1-2) Very Slightly Included

Inclusions are clearly visible but can be characterized as minor.

(SI1-3) Slightly Included

Inclusions are noticeable to a skilled grader.

(I1-3) Included

Inclusions are obvious and may affect transparency and brilliance.

Keegan's Jewelers
Norwood Location
1135 Washington Street
Norwood, MA 02062
(781) 769-5470
Store Information
Falmouth Location
205 Worcester Ct
Falmouth, MA 02540
1(508) 548-8300
Store Information
Norwood Hours
Mon-Wed:Monday - Wednesday:
10:00am - 5:00pm
Thursday:
10:00am - 5:30pm
Friday:
10:00am - 5:00pm
Saturday:
10:00am - 4:00pm
Sunday:
Closed
Falmouth Hours
Monday:
Closed
Tue-Wed:Tuesday - Wednesday:
10:00am - 5:00pm
Thursday:
10:00am - 5:30pm
Friday:
10:00am - 5:00pm
Saturday:
10:00am - 3:00pm
Sunday:
Closed
Jewelry
  • Engagement Rings
  • Women's Wedding Bands
  • Men's Wedding Bands
  • Rings
  • Earrings
  • Necklaces
  • Pendants and Charms
  • Bracelets
  • Chains
  • Watches
  • Special Jewelry
Designers
  • Allison Kaufman
  • Bering Time
  • Carla Corporation
  • Chatham
  • Citizen
  • Gems One
  • Keegan's Custom
  • LeStage
  • Malo Bands
  • Marathon
  • Ostbye
  • Pre-Owned Omega
  • Pre-Owned Rolex
  • Rembrandt Charms
  • Seiko
Our Store
  • About Us
  • Store Policies
  • Store Services
  • Privacy Policy
  • Terms and Conditions
Schedule an Appointment

Appointments and private showings available during & outside of regular business hours.

Important Pricing Information

Due to ongoing fluctuations in precious metal costs, some online prices may differ from the final sale price. Please contact us if you have questions about current pricing.

Newsletter

Enter your email below to sign up for our newsletter.

Follow Us
  • Return Policy
  • Privacy Policy
  • Terms & Conditions
  • Accessibility Statement

© 2025 Keegan's Jewelers. All Rights Reserved.

Powered by: Punchmark

Loading

Learn how we use cookies in our Privacy Policy or manage cookie preferences.