What Are the 4Cs of Diamonds?

Every diamond is graded on four qualities created by the Gemological Institute of America (GIA) in the 1950s:

• Carat – weight/size
• Color – how colorless the stone is
• Clarity – how clean it looks to the naked eye
• Cut – how well the facets interact with light

Master these four and you’ll never settle for less sparkle again.

Carat: It’s Not Just About Size

Carat measures weight (1 carat = 0.2 grams). Two diamonds of the same carat weight can look very different depending on cut and shape.

Quick rule of thumb we share with every client:

• 0.25–0.50 ct → delicate studs or pendants
• 0.75–1.00 ct → classic solitaires and everyday hoops
• 1.50–3.00+ ct → bold tennis bracelets and statement earrings

Pro tip: A well-cut 1.00 ct round can actually appear larger than a poorly cut 1.20 ct because more light returns to your eye.

Shop our 1ct Solitaire Diamond Engagement Rings

Color: The Less Color, the More Sparkle

Color is graded from D (completely colorless) to Z (noticeable yellow or brown tint).

ISAAC WESTMAN® diamonds are hand-selected in the G–H range for a reason:

Fun story: Our founders started in pearls in the 1980s and quickly learned that the same “colorless = better” rule applies to diamonds. That’s why every diamond tennis bracelet and huggie earring you’ll find here sits comfortably in G–H.

Clarity: Inclusions You Can (and Can’t) See

Clarity grades range from FL (flawless) to I3 (included).

For fine jewelry you’ll wear every day, we recommend VS1–VS2 or SI1. Here’s why:

• VVS – only for collectors or investment pieces
• VS – eye-clean, incredible value
• SI1 – still eye-clean in most sizes, huge savings

You’ll never see inclusions in our 3.0 CTW Diamond Huggie Earrings or 4.50 Ctw Tennis Bracelets because we only choose stones that look perfect on the hand.

Cut: The Most Important C (and the One Most People Ignore)

Cut is the only C humans control. A perfect cut turns a diamond into a mirror that returns 99% of the light that enters it.

The three things that make a diamond “sparkle like ISAAC WESTMAN®”:

1. Brilliance – white light reflected up
2. Fire – colored flashes
3. Scintillation – sparkle when you move

We only carry Excellent or Very Good cut grades. That’s why our customers tell us their pieces “look twice as big” as the same carat weight they saw elsewhere.

Popular cuts we love right now:

• Round brilliant (timeless)
• Oval (elongates the finger)
• Cushion (vintage romance)

Putting It All Together: Real-Life Buying Advice

For an engagement ring Go 1.00–1.50 ct, G–H color, VS2 clarity, Excellent cut. Our Platinum Six-Prong Solitaire is a customer favorite for exactly these specs.

For everyday earrings 0.50–1.00 ct total weight per ear, H color, SI1 clarity is perfect. Our Diamond Huggie Earrings in 3.0 CTW are lightweight enough for all-day wear yet dazzling.

For a treat-yourself tennis bracelet Look for 3–5 ctw, G color, SI clarity. Our 4.50 Ctw Diamond Tennis Bracelet in 14k white gold is the one our clients wear to the office and straight to dinner.

Caring for Your Diamond Jewelry (So It Lasts Forever)

Diamonds are the hardest substance on earth, but the setting isn’t. Quick care routine:

• Clean weekly with warm water, mild dish soap, and a soft brush
• Store separately from pearls (yes, even though we love both!)
• Have prongs checked once a year 

Why ISAAC WESTMAN® Diamonds Feel Different

We’ve been sourcing and crafting since the early 1980s. That means we know the exact cutters, the exact mines, and the exact factories that deliver the stones you see on our site. No middlemen surprises. Just four decades of saying “no” to anything that isn’t truly exceptional.

When you buy from us, you’re not just getting a diamond—you’re joining a legacy that started with pearls and grew into the full spectrum of timeless fine jewelry.

Ready to find the piece that feels like it was made for you?

Browse our full Diamond Collection or reach out—we’d genuinely love to help you choose something you’ll wear and love for the rest of your life.