A gemstone’s color is defined using three main key characteristics: hue, tone and saturation. Each plays a role in how we perceive a gem’s overall color, and together they create infinite variations— one of the reasons no two gemstones are ever exactly alike. Understanding how color is described can be the key to finding your…
Are unheated sapphires worth more than heated sapphires? In a lot of cases, unheated sapphires are more valuable, however it is a common misconception that heat treatment decreases the value of a sapphire or that somehow a heated sapphire is always less valuable than an unheated sapphire. In fact, heat treatment is always done to…
Most people have some idea of how to buy a diamond, as decades of education from the Gemological Institute of America and others have made the “Four C’s” a well-known set of criteria by which diamonds are judged. However, when it comes to sapphires, the rules change. You may be surprised that, unlike diamonds, there…
Sapphires are found in several regions across the globe, from the United States to Africa and Asia, and each region lends its sapphires unique characteristics. Sapphires are generally understood to form deep underground, either near the mantle-crust boundary (“magmatic” or “basaltic” sapphires) or deep within the crust as part of the movement of the tectonic…
When most people think of sapphires, they picture shades of blue—but there’s so much more to discover. Sapphires come in a wide variety of colors, including greens, blues, oranges, yellows, and even pink, but particolored sapphires are among the rarest and most visually striking, featuring two or more colors in a single gem. The Science…
Color can be quite subjective, especially in colored gemstones. Below is our guide to how we classify sapphire colors on our website. We use color-calibrated cameras to photograph each gem to showcase their truest color. However, sapphires can appear slightly different under varying lighting conditions. Because of this, we recommend submitting a video request once…
In the world of colored gemstones, beauty should never be sacrificed for size or weight—but unfortunately, that’s still the norm. Most colored gems today are cut with one of two goals in mind: maximizing weight or face-up size or some combination of those two. Ideal optical performance is typically not considered at all. To the…
What do we mean when we say our Montana sapphires are ethically and sustainably mined? In a world where ‘sustainability’ can sometimes feel like a buzzword, we believe in full transparency. Mining, by nature, may not seem eco-friendly, but we want to show you exactly why we stand by our claims—and how our direct, responsible…
We are often asked about clarity grades and clarity ratings on colored gemstones. There is a lot of confusion on this topic, so we’ve put together this article to discuss the topic and outline how we describe clarity here at Earth’s Treasury. Are there industry standards for clarity grades? No, not for colored gemstones. This…
To start, while we are asked about certificates from labs, it should be noted that all labs only issue reports, not certificates, and those reports are professional opinions, not guarantees. When it comes to guarantees, we guarantee that our stones are exactly as stated for gem species and treatment. If any of the major labs…
Sapphires have been known to occur in Montana for over 150 years and have been actively mined there for more than 100 years. Even with such a rich history, and a growth in recent interest, we believe they still do not yet have the recognition they deserve. Montana sapphires feature a beautiful range of colors…
We’re often asked about why and how certain gems are treated, particularly heat treatment. This short article will help explain why we heat some of our Tanzanite. Tanzanite is the trade name applied to blue-violet zoisite from Merelani, Tanzania. This gem is fascinating because of its rarity–so far it’s only ever been found in in the…
This page has been written to provide an overview of the heat treatment of Montana sapphires, as the topic is one that is still little understood by many. In the following sections we’ll explain why some sapphires are heated, what is done during the heat treatment process, how it changes the gemstones and how the…
We’re often asked about the various characteristics of the wide variety of colored gems by customers looking for the “perfect” gemstone. The choice of what gemstone might be right for you depends on a number of factors. In this brief article, I will try to outline some key considerations when selecting a gemstone. Hopefully it…
Aquamarine is the blue-green to blue gem variety of the of the mineral beryl. It’s been known and used as a gemstone since antiquity. The color of aquamarine can range from a very pale blue-green to a deep strong blue (“Santa Maria” blue is some of the finest blue aquamarine known); the value increases with the depth of saturation…
Emerald is one of the most well-known and desired colored gems known to mankind. There is evidence of emeralds being mined and used in jewelry going back to over 3,500 years before present. It is a variety of the gem beryl, colored green by minute traces of chromium, vanadium or both. While emerald has a…
Tanzanite is a trade name for deep blue to violet zoisite, colored by the presence of trace amounts of the element vanadium. It was first discovered in 1967 in the Merelani Hills of Tanzania and was named and marketed by Tiffany’s. While zoisite is found around the world, and is sometimes even gem-clear, the only…
Tourmaline is a remarkable gemstone, coming in an incredible variety of colors. Tourmaline can also be found in multi-colored forms, which is relatively uncommon in gemstones. It is actually a family of minerals that share a similar chemical structure. Most gem tourmalines are of the elbaite type, although certain dravite and liddicoatite tourmalines are…
It may come as a surprise, but not all garnets are the same—there are several major species of garnets. Learn more about the different major types of garnet.
We source all of my Montana sapphires directly from the mine owners, so we have full confidence in the gems we offer. The largest active mine in Montana is located in the Sapphire Mountains, in what is referred to as the “Rock Creek deposit,” located just west of Philipsburg, Montana. The area is wild and…
Chain of custody is the knowledge of every set of hands a gem has passed through between the moment it is dug from the ground and when it ends up in the hands of the final owner. Complete knowledge of the chain of custody is the only way to ensure that the gem you buy…
In the image below, we see people working under what appears to be difficult conditions, and indeed they are. In the foreground, men and women work with hand tools to turn over fresh soil, hunting for gem gravels containing precious blue sapphires. Behind them, others wash the gravel in open pits of muddy water, hoping to expose…
Introduction I had the good fortune to spend significant time in this area in the past few years, including a period of time working underground in the Oceanview Mine, currently the only mine where there is active drilling and blasting taking place. The tourmaline mines in San Diego County have produced more tourmaline than…
Introduction: Photographing Gems and Jewelry I thought I’d write a post about photographing gems and jewelry, since getting excellent photos of both is crucial for my business–and takes a significant amount of my time. It’s also a topic I frequently see discussed online. No matter what anyone tells you, getting good photos of gems is…
At Earth’s Treasury, we make finding your color easy with one of the widest selections of ethically sourced gemstones available, from Montana sapphires and garnets to tourmaline and emeralds. Our team of talented designers and jewelers is dedicated to creating custom gemstone jewelry that’s as unique as your story. Whether you’re drawn to classic pieces or dream up a one-of-a-kind engagement ring, we’ll guide you every step of the way to ensure your jewelry feels personal, original, and entirely you.
