4.99 ct Natural Blue Sapphire – Oval, Heated | GIA Certified | Madagascar

A natural 4.99 carat blue sapphire in an oval shape, heat-treated, from Madagascar. GIA Report #6237646036 records the species as Natural Corundum, the variety as Sapphire, the color as Blue, the shape as Oval, the cutting style as a Modified Brilliant Cut crown with a Step Cut pavilion, the transparency as Transparent, the weight as 4.99 carats, the measurements as 10.68 x 7.87 x 6.98 mm, the treatment as Heated, and the geographic origin as Madagascar. Face-up, Crescent Gems sees color zoning in this stone: a lighter, near-colorless zone through the center with blue around it. That observation is ours. The GIA report records the color as Blue and does not describe zoning.

What the GIA Report Records

GIA Report #6237646036 is a Sapphire Origin Report dated August 04, 2025. These are its fields, and this list is complete — the report states nothing else about this stone.

• Species: Natural Corundum. Variety: Sapphire.
• Color: Blue. No modifier, no trade-color name, no grade. GIA colored-stone reports assign no color grade.
• Shape: Oval. Cutting Style: Crown, Modified Brilliant Cut; Pavilion, Step Cut. In trade shorthand a brilliant-style crown over a step-cut pavilion is called a mixed cut — that is our summary, not a field on the report.
• Transparency: Transparent. Weight: 4.99 carats. Measurements: 10.68 x 7.87 x 6.98 mm.
• Treatment: Heated. This stone has been heat-treated, and the report says so.
• Geographic Origin: Madagascar — with GIA's own comment printed on the report: "Any statement on geographic origin is an expert opinion based on a collection of observations and analytical data." An expert opinion is not a verification, and we do not present it as one.
• Inscription(s): GIA 6237646036.
• Not on the report: no clarity grade, no cut grade, no quality grade, no trade-color name, and no description of color zoning. This layout of GIA report also carries no gemological characteristics panel. Anything on this page outside the list above comes from us or from general gemology, and is marked as such.

What Crescent Gems Observes

These are our own observations of the stone in hand. They are not GIA findings and the report does not record them.

• Color zoning. Face-up, a lighter, near-colorless zone runs through the center of the stone with blue around it. GIA's general published guidance on sapphire — not this report, which says nothing about zoning — states that "Color zoning—areas of different colors in a stone—is a common sapphire characteristic" and that "Blue sapphire often has angular zones of blue and lighter blue." This stone shows that pattern. It is a real feature of how the crystal grew, and it is why the stone looks as it does.
• Clarity. Eye clean in our assessment — no inclusions visible to the unaided eye at normal viewing distance. Under 10x magnification there are inclusions, as there are in almost all natural corundum. GIA colored-stone reports carry no clarity grade, so there is nothing on the report to compare this against.
• How the zoning presents. Where the lighter zone sits face-up shifts with the angle the stone is held and with how it is set. Judge it from the video or in hand rather than from one still photograph.

Buying Guidance

A few practical points to weigh before purchasing this specific stone:

• Look at the zoning yourself before you buy. How the lighter center and the blue around it balance face-up shifts with the stone's rotation in a mounting and with the viewing angle — use the video or an in-hand viewing rather than judging from a single static photo.
• Read the report alongside the stone. GIA Report #6237646036 records color, shape, cutting style, transparency, weight, measurements, treatment and origin. It does not describe the zoning, so do not expect to find it there.
• Consider mounting carefully. A setting that keeps the pavilion open (bezel or four-prong) will show the 10.68 x 7.87 x 6.98 mm oval's zoning more clearly than a setting that covers more of the stone's profile — discuss placement with your jeweler if you want a particular zone emphasized face-up.
• This is a heated stone, not an unheated one. The report states the treatment as Heated. If an unheated stone specifically matters to you, this is not that stone.
• Tell your jeweler the stone is heat-treated before any bench work involving heat, and avoid ultrasonic and steam cleaning.
• Use the Try Before You Buy option if you would like to see the stone in hand before finalizing the purchase.

Learn More About This Gemstone

• Sapphire Colors Explained
• GIA Guide
• Custom Ring Guide
• Madagascar Sapphire Guide
• Oval Sapphire Guide
• Sapphire Buying Guide

Why Choose this 4.99 ct Blue Sapphire?

It is a 4.99 carat natural blue sapphire with a GIA origin report: an oval of 10.68 x 7.87 x 6.98 mm, transparent, heat-treated, with Madagascar given as its geographic origin. Face-up it shows color zoning — a lighter, near-colorless center with blue around it — which is our own observation and not on the GIA report. We describe that zoning; we do not rank it.

Key Benefits of this Natural Blue Sapphire

• A GIA Origin Report
  Report #6237646036 records weight, measurements, shape, cutting style, transparency, color, species, variety, treatment and geographic origin, with GIA's own note that origin is an expert opinion.
• Treatment Stated, Not Implied
  The report states the treatment as Heated, and this page says so in the title, in the data table and here.
• Size
  4.99 carats, 10.68 x 7.87 x 6.98 mm — enough face-up area for a center stone in a ring or a pendant.
• Color Zoning You Can See
  A lighter, near-colorless zone through the center with blue around it. Our own observation, described rather than graded.
• Corundum
  9 on the Mohs scale — a property of the species, not a finding of this report.

Features

• Carat Weight: 4.99 Carats — GIA Report #6237646036
• Species: Natural Corundum — GIA Report #6237646036
• Variety: Sapphire — GIA Report #6237646036
• Shape: Oval — GIA Report #6237646036
• Cutting Style: Crown, Modified Brilliant Cut; Pavilion, Step Cut — GIA Report #6237646036
• Dimensions: 10.68 x 7.87 x 6.98 mm — GIA Report #6237646036
• Transparency: Transparent — GIA Report #6237646036
• Color: Blue — GIA Report #6237646036
• Treatment: Heated — GIA Report #6237646036
• Geographic Origin: Madagascar — GIA Report #6237646036, an expert opinion in GIA's own words
• Inscription(s): GIA 6237646036 — GIA Report #6237646036
• Color zoning: a lighter, near-colorless center zone with blue around it — our own observation, not on the report
• Clarity: eye clean at normal viewing distance — our own assessment, not a GIA grade
• Hardness: 9 on the Mohs scale — a property of corundum, not a field on this report

This 4.99 ct blue sapphire was hand-selected for its size, its cutting and the way the lighter center zone sits within the blue.

One of a Kind

This is a single natural gemstone, not a manufactured or lab-created replica — no two sapphires form with identical color, clarity and internal character. Once this stone sells, it's gone; there is no duplicate. GIA Report #6237646036 accompanies it, and the stone carries the inscription GIA 6237646036.

Care

Corundum is 9 on the Mohs scale, but a few habits keep this stone looking its best. Clean with warm water, mild soap and a soft brush. Avoid ultrasonic and steam cleaners. Store separately from other jewelry to prevent surface scratches to softer pieces, and remove the stone before swimming, exercising or household chemical exposure. Tell any jeweler working on it that the stone is heat-treated before bench work involving heat.

Why Customers Love This Gemstone

• GIA Documentation: Report #6237646036 states the species, variety, color, shape, cutting style, transparency, weight, measurements, treatment and geographic origin. It assigns no clarity grade and no quality grade.
• Nothing Overstated: the color on the report is Blue, the zoning is our own observation, and the origin is an expert opinion — each said in the place where the claim is made.
• Size: nearly 5 carats, with the zoning readable at wearing distance.
• Madagascar: given as the geographic origin on the report, with GIA's expert-opinion note carried alongside it.

Owning this 4.99 ct blue sapphire means owning one documented stone, described field by field on GIA Report #6237646036.

Perfect Uses for this 4.99 ct Blue Sapphire

• Collector centerpiece or display stone
• Statement pendant
• Bespoke large-format ring commission
• Center stone for a ring at nearly 5 carats
• Conversation piece for fine jewelry enthusiasts