4.04 ct Tanzanian Color-Change Sapphire — GIA Origin Report

Collector's Note

A substantial 4.04 ct natural sapphire from Tanzania with a GIA-documented color change from green-blue to purple under different lighting. The oval mixed cut gives the stone a broad face-up presentation; its deeper tone is balanced by the strength of the color-change phenomenon and the added collector value of documented unheated status.

Gemstone Details

Gemstone: Natural Color-Change Sapphire
Species: Natural Corundum
Weight: 4.04 ct
Shape / Cut: Oval Mixed Cut
Measurements: 10.46 × 7.33 × 5.69 mm
Origin: Tanzania
Color: Green-blue changing to purple
Transparency: Transparent
Treatment: No indications of heating

O50 Collector Evaluation

Otzera 50: 36/50 — Distinguished
Face-Up Performance: 65%

Treatment & Origin

GIA Sapphire Origin Report No. 2245074853 identifies natural sapphire of Tanzanian geographic origin with no indications of heating and documents the stone's color-change behavior.

Laboratory Documentation

Accompanied by GIA Sapphire Origin Report No. 2245074853, dated September 25, 2026.

Care & Setting

Sapphire is highly durable and suitable for jewelry wear with normal care. Clean with warm water, mild soap and a soft brush.

Digital Gem Passport

Accompanied by an Otzera Digital Gem Passport preserving its identifying details, laboratory documentation, origin and treatment disclosures, color-change phenomenon and O50 evaluation.