Inside Superior Grocers, Corona, CA
Certified engagement rings and loose diamonds, from a family counter you can visit.
Franzia Diamonds is a family-run jewelry counter tucked inside Superior Grocers, Corona, CA. Come see GIA and IGI certified diamonds in person, design a custom engagement ring with us at the bench, or compare natural and lab-grown side by side — with the grading report in your hand, not promised for later.
Walk in during store hours — or book a private appointment.Engagement rings, custom bridal, and loose diamonds under one counter.
On the counter today · 6 certified stones
oklch(seed) ✓
1.52 ct · Round brilliant
Excellent · F / VS1 · GIA #2s ago
$8,940Natural · Live2.04 ct · Oval
Excellent · D / VVS2 · GIA #11s ago · store · 231
$14,210Natural · Held1.21 ct · Emerald
Very Good · E / VS2 · IGI #34s ago
$5,180Lab-grown · Live · drop-ship3.07 ct · Cushion
Excellent · G / SI1 · GIA #1m ago
$19,400Natural · Live1.80 ct · Princess
Excellent · F / VS1 · IGI #1m ago · store · 884
$4,610Lab-grown · Held2.51 ct · Pear
Very Good · E / VVS1 · GIA #2m ago
$16,890Custom · Live
On the counter · what we carry
Every stone certified. Every ring made to order.
Franzia Diamonds carries GIA-certified natural diamonds and IGI-certified lab-grown diamonds, plus a small selection of finished engagement rings and the bench work to build a custom one for you. Everything on the counter is graded and everything on the counter is available to see in person.
A curated tray of certified diamonds, ready to view at the counter
Browse the current selection online, then stop by our counter inside Superior Grocers, Corona, CA to hold the stones under a loupe. Prefer a private appointment? Tell us what you are looking for and we will have a tray waiting when you arrive.
Natural and lab-grown, side by side
We carry both — clearly labeled, never substituted. Compare a GIA-graded natural stone next to an IGI-graded lab-grown one at the same 4Cs and see the difference in your hand, not on a spec sheet.
Every diamond ships with its GIA or IGI report
Naturals resolve to a GIA report; lab-grown resolve to an IGI report. Verify the report number on GIA Report Check or IGI Verify before you decide — nothing on our counter is ungraded and nothing is verify-later.
See stones in person — inside Superior Grocers, Corona, CA
Photos only tell you so much. Come see the sparkle under our loupe, on your finger, under everyday light. Walk in during store hours or reserve a private appointment for a longer look at a curated tray.
Custom engagement rings, made at the bench
Pick a center stone, then design the setting — metal, profile, side stones, engraving. Our bench manufactures the finished ring and typically delivers custom pieces in 1–3 weeks, with the original grading report in the box.
Configure your ring
step 3 of 4
Subtotal · $11,940
Manufactured in 7-10 business days
Custom engagement rings · at Franzia Diamonds
A ring designed at our bench, built around a diamond you picked in person.
Most jewelers hand you a setting book and call it customization. At Franzia Diamonds we start with the diamond — you choose a GIA or IGI certified center stone from our counter — then design the setting together: metal, profile, side stones, engraving. We manufacture through our vetted bench and hand you the finished piece with the original grading report.
- Configurable across metal, profile, side stones, and engraving
- GIA and IGI reports travel with the stone, from counter to finished ring
- Bench-built in about 1–3 weeks; we walk you through every stage in person
Trust · how a diamond gets to our counter
From the certified stone to the finished ring, the chain stays visible.
Every diamond at Franzia Diamonds traces the same five steps. We do not sell anything we cannot grade, and we do not deliver anything we have not personally inspected.
- 01
Sourced
Loose diamonds are hand-selected from vetted suppliers we have worked with for years — every stone individually chosen for cut quality, not bought by the parcel.
- 02
Graded · GIA or IGI
Natural diamonds arrive with their GIA report; lab-grown diamonds arrive with their IGI report. The report travels with the stone.
- 03
Inspected in-house
Each stone is checked at our counter against its report — measurements, clarity plot, fluorescence — before it goes into the case.
- 04
Viewed at Franzia Diamonds
You see the diamond in person under our loupe, in daylight, on your finger — inside Superior Grocers, Corona, CA. Ask any question at the counter.
- 05
Set, finished, delivered
If you go custom, our bench builds your ring and hands it to you with the original grading report. Complimentary cleanings and inspections for life.
Frequently asked
Quick answers before you visit.
If you have a question we have not covered, email us — a real person at the counter reads it and writes back. Or stop in during store hours at Superior Grocers, Corona, CA.
Come visit
Visit Franzia Diamonds inside Superior Grocers, Corona, CA — or start online.
Walk in during store hours at Superior Grocers, Corona, CA to see certified diamonds in person, or email us to reserve a private appointment. Browsing first? Preview what is on the counter online, then come try the ones you liked.
Franzia Diamonds · inside Superior Grocers, Corona, CA