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Gold Astra 4mm diamond stud flat back earring with a clear gemstone on a reflective surface
Close-up of an ear wearing Astra 6-prong 3.5mm diamond stud earring.
Side view of the Astra diamond flat back
Close-up of an woman's nose wearing Astra 6-prong 4mm diamond nose stud earring.
Close-up of an ear with gold Astra diamond earrings and measurements labeled.
Flat back labret sizing guide showing 18G and 16G gauges from 5mm to 9.5mm with ear piercing map
4mm Astra Diamond Flat Back Stud in 14k White Gold
Astra jewelry piercing styles group shot
4mm Astra Diamond Flat Back Stud in 14k Rose Gold
Gold Astra 4mm diamond stud flat back earring with a clear gemstone on a reflective surface
Close-up of an ear wearing Astra 6-prong 3.5mm diamond stud earring.
Side view of the Astra diamond flat back
Close-up of an woman's nose wearing Astra 6-prong 4mm diamond nose stud earring.
Close-up of an ear with gold Astra diamond earrings and measurements labeled.
Flat back labret sizing guide showing 18G and 16G gauges from 5mm to 9.5mm with ear piercing map
4mm Astra Diamond Flat Back Stud in 14k White Gold
Astra jewelry piercing styles group shot
4mm Astra Diamond Flat Back Stud in 14k Rose Gold
Home 4mm Astra GIA 0.25ct Diamond Flat Back Stud

4mm Astra GIA 0.25ct Diamond Flat Back Stud

$990 $1,980 Est. Retail Value
Gold Astra 4mm diamond stud flat back earring with a clear gemstone on a reflective surface
Close-up of an ear wearing Astra 6-prong 3.5mm diamond stud earring.
Side view of the Astra diamond flat back
Close-up of an woman's nose wearing Astra 6-prong 4mm diamond nose stud earring.
Close-up of an ear with gold Astra diamond earrings and measurements labeled.
Flat back labret sizing guide showing 18G and 16G gauges from 5mm to 9.5mm with ear piercing map
4mm Astra Diamond Flat Back Stud in 14k White Gold
Astra jewelry piercing styles group shot
4mm Astra Diamond Flat Back Stud in 14k Rose Gold
Gold Astra 4mm diamond stud flat back earring with a clear gemstone on a reflective surface
Close-up of an ear wearing Astra 6-prong 3.5mm diamond stud earring.
Side view of the Astra diamond flat back
Close-up of an woman's nose wearing Astra 6-prong 4mm diamond nose stud earring.
Close-up of an ear with gold Astra diamond earrings and measurements labeled.
Flat back labret sizing guide showing 18G and 16G gauges from 5mm to 9.5mm with ear piercing map
4mm Astra Diamond Flat Back Stud in 14k White Gold
Astra jewelry piercing styles group shot
4mm Astra Diamond Flat Back Stud in 14k Rose Gold

Diamond Size

4.0mm
2.5mm 3.0mm 4.0mm
Size Chart

Sizing Piercing Jewelry

Choosing the right size ensures comfort, healthy healing, and a flawless look. Use this guide to understand gauge, length, and diameter, then confirm your fit with the conversion charts below.

What Is “Gauge”?

The gauge of your piercing is the thickness of the bar that passes through your piercing—i.e., the barbell’s thickness. Note the system is inverse: a lower number = thicker bar. For example, a 12G barbell is thicker than a 20G barbell.

Piercing Jewelry “Length”

The length of your piercing jewelry refers to the wearable span of a straight or curved barbell—the section that sits inside the piercing. It’s measured end-to-end on the bar and excludes any ends, balls, or charms.

measuring length of a flat back earring measuring length of a nose ring



measuring length of a straight barbell measuring length of curved barbell


Piercing Jewelry “Diameter”

The diameter is used for circular styles—hoops, captives, clickers, seam rings, and circular barbells. Measure from the innermost, widest point across the inside of the hoop.

measuring diameter of captive bead ring measuring diameter of circular barbell

Standard Piercing Sizes

Check the chart below for typical starting sizes. Like clothing, anatomy varies—your ideal size may differ.

💡 Tip: Measure a comfortable piece you already wear to confirm your fit.


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Made to order: Ready in 1–2 weeks

Solid 14k Gold

Jeweler Direct

Handmade

Piercing Advisor

Ethical Luxury

Lifetime Warranty

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Product Description

Description

Bold, radiant, and designed to stand out, the Astra 4mm Diamond Flat Back Stud features a striking genuine diamond set within Fresh Trends’ signature 6-prong setting. Whether styled as a focal point in a curated ear or worn solo for timeless sparkle, the Astra brings luxurious shine with elevated craftsmanship.

  • .25ct (4mm) GIA Certified Diamond
  • Diamond Clarity: VS1
  • Solid 14k Gold | Hypoallergenic & Nickel-free
  • 18G threadless and 16G threaded/threadless options
  • Post lengths: 3/16" (5mm), 1/4" (6mm), and 5/16" (8mm)
  • Made to order in the USA
Product Details
Materials
Shipping

Pairs Well With

FreshTrends mint green travel jewelry box, closed front view with gold FT Est. 2003 logo Close-up of travel jewelry box interior holding gold piercing studs, earrings, and CZ body jewelry
Travel Jewelry Box $17
Flat back earring insertion tool beside a gold CZ flat back stud, showing tool and jewelry separately Insertion tool being used in a helix piercing on a model, with gold CZ chain connector studs in lobe
Flat Back Earring Easy Insertion Tool $14
Four Astra Diamond Stud Earrings in various sizes White gold diamond earring on a white background
Astra Diamond Stud Earring $279
14k yellow gold diamond bubble flat back studs, small and large sizes shown side by side on marble surface 14k yellow gold diamond bubble flat back stud small size, straight front view on white background
Diamond Bubble Flat Back Stud $313
14k white gold crescent climber cartilage stud with 5 pear-cut white sapphires, front view Reverse view of white sapphire crescent stud showing internally threaded post and flat back disc
White Sapphire 5 Pear Crescent Climber Cartilage Earring $729
14k yellow gold peridot pear-shaped flat back labret stud with prong setting, angled product view Four-step illustrated guide showing how to insert and secure a threadless push pin flat back labret stud
Peridot Pear Shaped Flat Back Earring $252

Jeweler-Direct Pricing

Jeweler-Direct means crafted, just for you. By skipping the middleman, we eliminate traditional retail markups — so you can enjoy luxury piercing jewelry without the inflated price.

Fresh Trends Price — $990

Est. Retail Value — $1,980

Fresh Trends Piercing Advisor™

Our complimentary Piercing Advisor™ service ensures your jewelry fits perfectly. After your order, a specialist reviews your selection, verifies your size, and guides you through any adjustments. For jewelry to be eligible for an adjustment, FreshTrends Piercing Advisor™ must be added to your cart at the time of original purchase.

Why It Matters:

• Anatomy varies, and size is crucial

• A specialist confirms your fit before we craft your piece

• You get a flawless, comfortable result—every time

Piercing Advisor Service

Handcrafted Just For You!

Our in-house jewelry designer and artisans create one-of-a-kind piercing jewelry from solid 14k gold and 950 platinum, always 100% nickel-free.

Each piece is made-to-order and never mass-produced, allowing for many gemstone and size options for the perfect fit. We take pride in hand-crafting fine body jewelry in the USA.

Fresh Trends Fine Jewelry

Because every piercing deserves its masterpiece.

Ready to Gift

Your jewelry arrives in our signature packaging—a keepsake box with a soft green pouch and a Wear & Care Guide. Premium pieces are showcased in an LED presentation box that elevates every gifting moment.

Fresh Trends Packaging

Fresh Trends® Lifetime Warranty

Every piece we craft is designed for lifelong wear. If your jewelry ever shows a manufacturing defect, we’ll repair or replace it—complimentary, for life.

Lifetime Confidence. Handmade Quality.

Gold earring with clear gemstones on a soft pink fabric background

Sustainable Jewelry

We use recycled metals to help reduce the carbon footprint of manufacturing and the negative impact of metal mining.

We plant one new tree per order in partnership with Ecologi to help restore nature and reduce the carbon footprint of our operations.

ecology

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