Sister stone to the ruby, most people think blue when they think sapphire. Blue is sapphire's best-known color. Sapphire isn't always blue - we find sapphire in every color in, and under, the rainbow. One of the world's most prized stones is the orange sapphire known as apparatchik. Its lotus-flower color offers up fiery beauty. There are cool green sapphires, warm golden sapphires, pretty pink sapphires... in the world of the sapphires, there's a color that's right for you. There is also a sapphire that changes color when moved from natural to incandescent light. It's color-change sapphire and it can be glorious! It can be a brilliant color change from blue to a rich purple or it may be a subtler change. Whether brilliant or subtle, the color-change of sapphire is compelling. Sapphire is corundum and a 9 on the hardness scale. It's wearable and wonderful. Sapphire is September's birthstone.

Inclusions

Sapphire has type II clarity. Sometimes have silk, rutile, boehmite, apatite, calcite, or zircon crystals. Fingerprint and negative crystal inclusions. Hexagonal growth and color zoning. Untreated stones will usually have inclusions intact. Heat-treated stones will have fracture halos, discoid fractures, or snowballs around crystal inclusions (untreated stones from magmatic areas might also show these characteristics). Silk will be broken and might show sintered areas, especially around the girdle.

Natural & Untreated Sapphires

When considering colored gemstones, specifically sapphires, understanding the terms “natural” and “untreated” is crucial to making an educated decision. Many people confuse natural for meaning untreated, and vice versa. In optimal circumstances, both terms should apply to the gemstone, but that is rarely the case with what is currently in the market.

In concise detail, an untreated sapphire has been taken from the ground and then faceted. Nothing was done to the stone to alter the natural beauty, which only elements and processes in the earth created naturally. These sapphires are exceptionally rare and Valluable. For this reason, sapphires are extraordinarily unique from one to the next.

The word “natural” identifies a sapphire crystal that has been developed in the ground, not synthetically created or treated in a lab. The word “untreated” means that a sapphire has not undergone any heat or chemical treatments to improve its color or clarity.

Natural & Untreated Sapphires in 2020

In 2020, nearly all sapphires and sapphire jewelry from online sources and in traditional retail stores are described as “natural”. It’s important to take note that the term ‘natural’ is not always a complete description of how the gemstone looked when it came out of the ground. Although ‘natural’ means the stone was created in the earth, by the earth, quite often the color and clarity have been improved through heat treatments, being aware of the differences between a heat-treated sapphire and one that has not been heat-treated is important to learn more about.

Most sapphires are heated up to a temperature of 1800 C° over several days. This allows for the color and clarity to improve. This is called ‘dry’ heat because nothing is added to the heating chamber other than the sapphire that came from the ground. However there are less ethical treatments that are often done to sapphires that are unfortunately not always disclosed to the consumer. These types of treatments can radically change the color and clarity of very inferior sapphires. This type of heat treatment of referred to as chemical heating or heating with additives such as glass and beryllium coloring agents that fill cavities and cracks in the sapphires.

Because some techniques to alter stones have become so sophisticated, many of these sapphires can look indistinguishable from fine-quality untreated sapphires. And with the trend in 2020 going towards colored gemstones, these may be very popular options. However, they will never maintain the true value of a real natural sapphire. We do not advocate purchasing these types of sapphires, hence we do not offer any heat-treated sapphires other than ‘dry’ heat-treated ones.

Color Change - Optical Phenomena

While color-change sapphires come from a variety of locations, the gem gravels of Tanzania are the main source. Color change sapphires present gem lovers with an opportunity to own the rare and stunning color change effect in a gem other than alexandrite, garnet, spinel, tourmaline, or diaspore. While the colors tend to vary depending on the locale, in general, they change from blue to purple. You can observe the color change in this gem by viewing it interchangeably in natural and incandescent light.

Color Change Sapphire -Cat's-Eye

The term cat's eye, or chatoyancy, is used to describe a phenomenal optical property in gemstones, in this case, sapphire. The effect, when present, appears as a bright, narrow slit similar to the pupils in the eyes of your favorite feline. This phenomenon is caused by parallel fibrous or needle-like inclusions that interfere with the passage of light through the crystal, scattering and reflecting light to the viewer as a thin line.

Star Sapphire

Star sapphire exhibits the optical phenomenon called asterism, a star-like pattern created on the surface of a gemstone when light encounters parallel fibrous, or needle-like, inclusions within its crystal structure. The light that strikes the inclusions within the gem reflects off of the inclusions, creating a narrow band of light. When two or more intersecting bands appear, a star pattern is formed. Depending on the crystal, the star typically has six rays, but on occasion, twelve rays.

 

Treated Sapphires

Treated sapphires are very common; they represent the norm in today’s market and are very readily available. Consumers looking to long term preservation and growth in value should consider unheated sapphires more than traditionally heated sapphires. Be sure to ask questions about any treatments that may have been subjected to a sapphire you are considering to purchase.

There is no substitute for the beauty of an untreated sapphire. New treatment protocols are continuously being developed. Trained gemologists can often spot the telltale signs of gem treatments, but advanced technology is often used for 100% accuracy in treatment detection. We always disclose treatment on our stones if there is any and we describe our stones to the best of our abilities as ethical sellers.

Determining if a sapphire has been heated is normally a simple task done by a trained gemmologist who is familiar with inclusions in sapphires. When sapphires are heated at high temperatures, the natural internal inclusions change drastically. Viewing these radically changed internal inclusions is the “ID” of a heated sapphire. Madagascar pink sapphires are heated for as little as five minutes at low temperatures where no internal inclusions are affected.

Because no internal inclusions are affected it becomes VERY difficult to determine if a pink sapphire has been heated. High tech equipment can be used to detect trace mineral content changes within the stone. This type of equipment is very costly and only used by high quality laboratories.

To help illustrate the point of how difficult it can be to determine heat treatments in pink sapphires especially, we have given multiple laboratories the same Madagascar pink sapphire for testing to determine if it had been heated or not. In many cases, we were given conflicting results on the same stone from different laboratories. One lab would determine that the pink sapphire was heated and the other would determine it had not been heated. The reputable labs do an excellent job in most cases, but results on heating vs. no heating on pink sapphires from Madagascar can be about as worthless as origin determination. Pink sapphires from Sri Lanka and other locations such as Burma are a different story. These stones are usually heated at very high temperatures along the lines of extreme heating done with the yellow and blue sapphires that are treated, so treatments are much easier to detect.

Treatments, Value, and Other Details

Most (if not all) sapphires and sapphire jewelry seen online and in retail stores will be described as “natural” sapphires. These natural sapphires are usually not accompanied by proper disclosures regarding the treatments that they have undergone.

Blue Sapphire Color

The most important characteristic to consider when determining a sapphire’s price is always its color grade. The best color for a natural blue sapphire is an intense, velvety, deep royal blue. This color of sapphire would be considered AAA quality, the rarest and most Valluable. The second best color is a medium-rich blue or AA quality. Any blue sapphires that have a slight gray undertone fit into the A category.

Finally, sapphires that have a very dark and opaque blue color are considered B-quality grade. The 3 keys to color grading are identifying hue, tone, and saturation. Color is graded on these factors face up on a white surface. The hue should be royal blue, the tone should be deep blue and the saturation should be even throughout the gem.

Sapphire Clarity Grading

After color, clarity is another important factor that has an impact on a gemstone's price and rarity. There are three types of clarity grades for gemstones such as sapphires: Type 1 stones, Type 2 stones, and Type 3 stones.

• Type 1 stones - These stones will generally be "eye-clean," meaning that they have no inclusions visible to the naked eye.
• Type 2 stones - These typically show some inclusions visible to the naked eye. However, they don’t detract from the overall beauty of the gemstone.
• Type 3 stones - These gemstones will almost always have inclusions, and they will always be visible to the naked eye.

Overall, most gemstones do have some type of inclusion, even if it isn't eye-visible. Generally speaking, the fewer inclusions a gemstone has, the rarer it is. Thus, the price will be higher for Type 1 stones than Type3

 

Sapphires still fall into the general clarity grading for gemstone categories (Types 1, 2, or 3). However, there are more specific terms that are directly related to the clarity of sapphires. They include concaves, eye grade, loupe grade, and transparency.

 

• Concave - This is a natural mark found on the surface of sapphires. They normally form on the girdle and don’t interfere with the stone's beauty.
• Eye Grade - This evaluates the overall clarity of the sapphire when viewed without magnification.
• Loupe Grade - This differs from eye grade because the clarity is checked under 10x magnification.
• Transparency - This is the relative ability a sapphire has to transmit light.

 

There are different types of inclusions that sapphires can have. Needles are long, thin mineral deposits, which are referred to as silk inclusions and are the most common type. Silk inclusions can form interactions within the sapphire, known as the "star" effect. The price of a sapphire drops as it contains more inclusions, which affect the overall stability of the gemstone.