Sunday, March 20, 2016

Waves of Aqua

Photo courtesy of
Ever been caught up in a great big wave? Water seems all by itself very innocuous, harmless even. At times it feels tranquil and peaceful; but in an instant, it can become stormy and powerfully devastating. It seems fitting that people before us selected aquamarine as the stone to represent all of these feelings; using it as an amulet for health and happiness in times of peace, but also as protection against the perils of stormy seas. It even has the cool color to match...
A trillion-cut aquamarine. Photo courtesy of

What is aquamarine? It's a gemstone from the beryl family, meaning that it is a brother to stones such as heliodor and the more famous emerald. Unlike emerald however, aquamarine in its best quality is a fairly inclusion-free stone, which makes it a lot less difficult to cut. When it does bear inclusions, a tell-tale sign of a natural aquamarine is the tube-like inclusions resembling ''rainfall". It is the more commonly known birthstone of March and is best known for its enchanting blue-green color.  While some people covet the pure light blue color which is generally induced through heating, the greenish-blue hue is a beautiful sight to behold.

A rough crystal of aquamarine in its typical growth structure and etching along the faces. Photo courtesy of
It comes out of nature looking quite intriguing, really. Though they come in all sizes, aquamarine is most beautiful in rough form when they grow to be large hexagonal prisms. It is then that we can see the fascinating etch marks that run up and down the faces of the crystal. Not one is ever similar to the other, which makes each crystal a discovery of sorts.

                              The Dom Pedro Aquamarine at the Smithsonian National Museum of Natural History.                                       Photo courtesy of
There are some exceptional specimens which grace the halls of great museums, however this hardly means that aquamarine is an unattainable gemstone. In fact, it's a stone which is quite tolerant to everyday wear; which makes it a great choice for jewelry. While of course it's always recommended to treat your gems carefully, aquamarine has a fairly high hardness level which lends itself to both casual and evening wear. It is not recommended to clean them in an ultrasonic machine if heavily included; however a simple cleaning with mild soap and a toothbrush is enough to restore its beautiful luster.

Photo courtesy of

Aquamarine ring. Photo courtesy of
Dangle earrings featuring aquamarine and diamond. Photo courtesy of
Rough aquamarine in jewelry. Photo courtesy of

I've always loved to watch waves rush up to the shore and then pull back away. It's entrancing, almost like it's calling out for you to join the tide. Finding such a feeling in a stone is so singular, don't you think?

Sunday, March 06, 2016

Are You Seeing Stars? We Are!

Asterisms recently made the news when a giant star sapphire was discovered in Sri Lanka; the owners claim that it is indeed the largest sapphire displaying an asterism ever found. They intend to sell the "Star of Adam" at auction with the stone currently valued at 100 million dollars.  But what is an asterism exactly and how does it occur?  Where and how often does it happen?
The ''Star of Adam'', weighing in at 1404.09cts is said to be the world's largest sapphire. Photo courtesy of
An asterism, as the name suggests,  is a reflection effect that is seen in some gemstones that takes the shape of a star. It's the result of light reflecting off of the many intersecting inclusions inside the stone. While most gemstones are regularly sought after for their clarity or lack of inclusions, in asterism-bearing gems, it is these very inclusions which give them value. But not just any inclusions can induce this phenomenon; certain conditions are required to produce this:

Diagram illustrating the parallel and long inclusions crossing in different directions to create the asterism effect. Photo courtesy of
1) The inclusions are generally:
- Long
- Thin
- Numerous
- Parallel to one another

These can be made up of anything from tube-like cavities, to rutile crystals (as is the case in sapphire). If this were not enough, there needs to be at least two oriented sets of inclusions that intersect in order to produce the star shape; so it takes quite the included material to achieve this. When light hits these inclusions, the reflection effect will occur at a right angle, creating the star-shape that you see both in the diagram above, and the picture below.

An asterism-bearing corundum, with arrows showing the likely location of the inclusions causing the effect. Photo courtesy of a reader, Marine Explorer.

2) The cut of a stone is also important. Ideally, the stone should be cut into a cabochon, or a polished rounded surface. This is because the effect is best seen rolling off of this rounded surface. Further, the cabochon lends its flat base to better display this effect.
A star-ruby displaying the hexagonal growth structure typically seen in ruby. Photo courtesy of
Star-diopside with its typical 4-branched star. Photo courtesy of
The rarely seen asterism in moonstone. Photo courtesy of
Star-Almandine, showing the angled 4 branches typically seen in garnet. Photo courtesy of
Rose quartz manifesting asterism. Photo courtesy of

So in what stones do asterisms occur? As mentioned earlier, it's the included materials that will display this effect; meaning that this can be seen in quite a few stones: you'll see this generally in rubies, sapphires, spinel, rose quartz (which can even display diasterism-12 branched star), garnet,  diopside and in rare cases,  moonstone. Stars can also have varied appearances based on the number of branches they possess; This can allow us to distinguish them. For instance, diopside has a 4-branch star whose branches are generally 90 degrees from one another, whereas garnet will display 4 branches at a slight angle. 

Examples of disclosed synthetic star-sapphires. Photo courtesy of
While synthetic materials in these gemstones have the ability to manifest this phenomenon as well, thankfully they are fairly easy to detect. Naturally occurring asterisms in gemstones will often have a hazy, almost blurred appearance, which is quite normal for anything produced in Nature. By comparison, the asterisms seen in synthetic materials are often too sharp and distinctively fine. It's very much one of those "too good to be true'' scenarios.

In case you were wondering, not all asterism-bearing materials have million dollar price tags (thank goodness!). In the case of star-sapphire for example, prices average anywhere between 1200-1600$ US per carat, when dealing in the finer quality materials. Let us know if you'd like to have one in your arsenal!