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The Beauty and Mystery of Natural Sapphires

Sapphires, with their rich hues and stunning brilliance, have captivated jewelry enthusiasts and collectors for centuries. Known for their exceptional hardness and vibrant colors, sapphires are a popular choice for various types of jewelry. However, not all sapphires are created equal. Understanding the differences between natural, heated, unheated, and treated sapphires is essential for any gemstone enthusiast. In this blog, we'll explore these distinctions and offer insights into how to identify each type.

What is a Natural Sapphire?

A natural sapphire is a gemstone that has been formed over millions of years under the Earth's surface. These sapphires are mined and cut without undergoing any artificial enhancements. They are prized for their rarity and the unique characteristics that come from their natural formation processes.

Heated Sapphires

One of the most common treatments for sapphires is heat treatment. This process involves heating the sapphire to high temperatures to enhance its color and clarity. Heat treatment can bring out more vibrant hues and reduce the appearance of inclusions, making the sapphire more visually appealing.

Natural heated sapphire set in 18k white gold with diamonds
Natural heated sapphire set in 18k white gold with diamonds

Unheated Sapphires

Unheated or untreated sapphires are those that have not been subjected to any form of artificial enhancement. These sapphires retain their natural color and characteristics as they were formed in the Earth. Unheated sapphires are highly sought after for their purity and natural beauty.

Natural Unheated Green sapphire
Natural Unheated Green sapphire

Various Treatments and Their Effects

In addition to heat treatment, sapphires can undergo several other treatments to improve their appearance:

  1. Diffusion Treatment: This involves heating the sapphire with certain elements, such as beryllium, to alter its color. The treatment only affects the surface of the stone, and the color may not be as durable as naturally colored sapphires.

  2. Fracture Filling: This process fills the fractures in a sapphire with a glass-like substance to improve its clarity. While this can enhance the appearance of the stone, it also makes it more fragile.

  3. Surface Coating: Some sapphires are coated with a thin layer of color to improve their appearance. This treatment is often less durable and can wear off over time.

How to Determine the Type of Sapphire

Determining whether a sapphire is natural, heated, unheated, or treated requires careful examination and sometimes advanced testing. Here are some steps to help identify the type of sapphire:

  1. Visual Inspection: Look for inclusions and color zoning. Natural sapphires often have characteristic inclusions that can be seen under magnification.

  2. Certification: Obtain a certificate from a reputable gemological laboratory. These certificates provide detailed information about the sapphire, including whether it has been treated.

  3. Advanced Testing: In some cases, advanced tests such as spectroscopy or infrared analysis are necessary to determine the specific treatments a sapphire has undergone.

Free Appraisal Service

We offer a free appraisal service to help you determine the authenticity and type of your sapphire. Our expert gemologists will inspect your sapphire and provide a detailed report on its characteristics, including whether it is natural, heated, unheated, or treated. This service is designed to give you peace of mind and confidence in your gemstone purchase.

Sapphire appraisal being conducted in bucks county PA


Understanding the differences between natural, heated, unheated, and treated sapphires can help you make informed decisions when purchasing these beautiful gemstones. Whether you're a collector or simply an admirer of fine jewelry, appreciating the unique qualities of each type of sapphire can enhance your enjoyment of these exquisite stones.


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