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GIA · IGI · HRD Certified

Certified Loose Diamonds

Hand-pick from thousands of GIA, IGI, and HRD-certified loose diamonds — round, princess, oval, cushion, and more. Natural and lab-grown, each verified by an independent gemological laboratory.

Starting from $113

Round brilliant cut diamond
Princess cut diamond
Cushion cut diamond
Oval cut diamond
Family-Owned Since 1999 Certified Conflict-Free Diamonds Free Insured Shipping 30-Day Money-Back Guarantee 222+ Five-Star Google Reviews

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How to Buy a Certified Loose Diamond

Choosing a loose diamond is the most important step in creating the perfect engagement ring, pair of diamond studs, or custom diamond pendant. At USA Jewels, every diamond in our inventory is conflict-free and independently certified by GIA, IGI, or HRD — so you know exactly what you are getting before you buy.

Understanding the 4Cs

The four characteristics that determine a diamond's quality and value are Cut, Color, Clarity, and Carat Weight. Of these, cut is the most important — a well-cut diamond reflects light beautifully regardless of size. Our diamond buying guide explains each factor in detail, and our pricing guide shows how the 4Cs affect cost.

Natural vs Lab-Grown Diamonds

Both natural and lab-grown diamonds are real diamonds with identical physical and optical properties. Natural diamonds are formed over billions of years deep within the Earth, while lab-grown diamonds are created in controlled environments. Lab-grown diamonds offer the same brilliance at 60-80% less, making them an excellent choice for budget-conscious shoppers. We carry both, fully certified.

Choosing the Right Shape

Diamond shape is a matter of personal style. The round brilliant remains the most popular for its unmatched sparkle. Princess and cushion cuts offer a modern look, while oval and pear shapes create an elongating effect on the finger. Explore our shape guide to compare all 10 shapes.

Pair Your Diamond with the Perfect Setting

Once you select your diamond, pair it with one of our engagement ring settings in 14K or 18K gold or platinum. Or design your own ring from scratch. Our team will set, size, and polish your piece in our workshop. Need help? Contact our diamond experts for a free consultation.

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Customer Stories

What Our Customers Say

★★★★★

“My now fiancé decided to work with Deep and Dave to custom make my engagement ring — which is 100% perfect. They do incredible work and the ring exceeded all expectations.”

Casey O. — via Google

★★★★★

“USA Jewels is a hidden gem! The custom ring I designed turned out incredible. Fair prices and unmatched quality. My fiancée was blown away.”

Trevor G. — via Google

★★★★★

“They made the process so easy and stress-free. They answered all my questions and helped me find the perfect ring within my budget. Highly recommend!”

Ashley P. — via Google

Diamond engagement ring on hand

Your Forever Moment

Find the Diamond for Every Milestone

From the perfect engagement ring to a milestone anniversary gift, every certified diamond in our collection is hand-selected for brilliance and value. Choose your stone, choose your setting, and create a piece that will be treasured for generations.

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Common Questions

Frequently Asked Questions

What are the 4Cs of diamond quality?
The 4Cs are Cut, Color, Clarity, and Carat Weight. Cut has the biggest impact on brilliance and sparkle. Color grades range from D (colorless) to Z (light yellow). Clarity measures internal inclusions. Carat is the diamond's weight. Learn more in our Diamond Buying Guide.
What is the difference between natural and lab-grown diamonds?
Natural diamonds form deep in the Earth over billions of years. Lab-grown diamonds are created in controlled environments using High Pressure High Temperature (HPHT) or Chemical Vapor Deposition (CVD). Both are real diamonds with identical physical, chemical, and optical properties. Lab-grown diamonds typically cost 60-80% less than natural diamonds of equivalent quality.
What does GIA, IGI, or HRD certification mean?
These are independent gemological laboratories that grade diamonds. GIA (Gemological Institute of America) is the most widely recognized. IGI (International Gemological Institute) is a leading lab for both natural and lab-grown diamonds. HRD (Hoge Raad voor Diamant) is a respected European lab. Each provides an unbiased report detailing the diamond's 4Cs, measurements, and quality characteristics.
Which diamond shape is the most popular?
The round brilliant is by far the most popular shape, accounting for about 75% of all diamonds sold. It offers maximum brilliance and fire due to its 57-58 facets. Princess, cushion, and oval shapes are also very popular choices. Browse all shapes in our diamond search.
How do I choose the right carat size?
Carat size depends on your budget and preference. A well-cut 0.90ct diamond can appear as large as a poorly-cut 1.00ct — prioritize cut quality first. For engagement rings, the most popular range is 0.75ct to 1.50ct. Consider the ring setting too: halo settings make the center stone appear 0.25-0.50ct larger.
Are your diamonds conflict-free?
Yes. Every diamond we sell — both natural and lab-grown — is 100% conflict-free and ethically sourced. We adhere to the Kimberley Process and work only with suppliers who share our commitment to responsible sourcing. Every diamond comes with an independent certification from GIA, IGI, or HRD verifying its origin and quality.
Do you offer free shipping and returns?
Yes. Every diamond ships free with full insurance via FedEx or UPS. We also offer a 30-day money-back guarantee — if you're not completely satisfied, return your diamond for a full refund. All diamonds also come with a lifetime diamond upgrade policy.

Need Help Choosing?

Our diamond experts are here to help. Call, email, or visit our showroom.

Call (877) 872-9909 Contact Us