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Adornments Watch

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Gemology Corner

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Jewelry advice from Adornments’ own resident jewelry designer and GIA (Gemological Institute of America) graduate: Alexis Anbari! How to shop for quality gemstones, what to look when buying jewelry, how to have a custom piece designed just for you, and more!

 

April’s Birthstone: Diamonds!

Monday, April 26th, 2010

Diamonds are one of the most interesting and attractive gemstones. They’re also one of the most valuable minerals on Earth and the birthstone for the month of April!

I recently wrote a post on shopping for Diamonds and the 4 C’s, and since that article was so technical, I thought I’d take a different tact with this one. So here are some fun facts about diamonds!

  • Diamonds are the hardest natural mineral on earth, by a lot! They are four times harder than next hardest mineral, corundum (sapphires and rubies).
  • They conduct heat 4 times better than copper (this fact is used to test for diamond simulants).
  • Round brilliant cut diamonds have 58 facets.

ancient egyptian marriage

  • The tradition of wearing engagement and wedding rings on the 3rd finger of the left hand dates back to Ancient Egypt. The circle of the band represents eternity, and the ring finger contains the “vena amoris”, the vein of love which runs directly to the heart.
  • The word diamond comes from the Ancient Greek word, adamas, meaning unconquerable. The Ancient Greeks believed diamonds were splinters of stars fallen to earth.
  • Diamonds are believed to represent strength, courage, and invincibility (not surprising considering their durability!).
The Great Star of Africa

The Great Star of Africa was set into the Royal Scepter of King Edward VII of England in 1907. It's now kept in the Tower of London.

  • Until recently, the largest cut diamond was the Great Star of Africa, weighing 530 cts. It was cut from the Cullinan 1 diamond discovered in 1905 in South Africa, which was 3,106cts and yielded 105 cut gemstones.
  • Currently the largest cut diamond is the Golden Jubilee, a fancy yellow brown diamond of 545.67 cts.
  • Diamonds come in a wide range of colors besides white (or colorless). One of the most famous fancy colored diamonds is the Hope diamond- the largest deep blue cut diamond.

Michelle Pfieffer wearing the Hope Diamond.

  • In India, one of the largest cutting centers in the world, about 3 million people work in the diamond industry.
  • 25% of Israel’s total export earnings come from diamonds.

Workers polishing diamonds.

  • It’s estimated that only about 500 tons of diamonds have ever been mined in recorded  history so far.
  • Only 1 diamond in a million weighs more than a carat.
  • 250 tons of ore need to be blasted, crushed, and processed to yield just one carat of diamond rough.
  • Diamonds lose approximately 50% of their weight in the cutting and polishing process.

March’s Birthstone: Aquamarine!

Wednesday, March 24th, 2010

Aquamarine is a lovely light blue gemstone. The name actually comes from the Latin phrase meaning “water of the sea.”

Aquamarine is a member of the Beryl species of gemstones, which comes in a wide variety of colors including yellows, greens, blues, pinks, and even a rare red! Aquamarine is second in popularity only to emeralds among the beryl family, though there are several more rare gemstones as well such as Heliodor and Morganite . It’s color ranges from light blue to bluish green, caused by trace amounts of iron within the crystal structure. The most valuable color is a moderately strong, medium dark blue to slightly greenish blue.

Heliodor- member of the Beryl family

Morganite- member of the Beryl family

Aquarmarines are often fashioned as emerald cuts or as round or oval brilliants to take advantage of the fact that most are “eye clean” (meaning that you can’t see any inclusions of fractures within the stone with the naked eye).  In order to show an intense color, aquamarines frequently have to be cut as larger gemstones. Though, there are some stones from African mines (Nigeria, Madagascar, Mozambique) that can show an intense blue color even in smaller sizes.

The colors of Aquamarine

Aquamarine is an affordable gemstone due to it’s availability. Since 1811, the world’s biggest source of aquamarine has been Brazil. Other sources include Pakistan, Australia, Kenya, Zambia, the U.S, and China.

Aquamarines were originally associated with the Zodiac sign of Scorpio (how this got changed to March is a bit of a mystery, though I personally suspect that jewelery professionals have something to do with it..). It was believed this clear, blue gemstone came from the treasure chests of mermaids.  Gemstones were long believed to possess magical properties and Aquamarines endowed the wearer with foresight, courage, happiness, higher intelligence, and youth. They were used to treat anxiety and help keep sailors safe and prevent seasickness.

Aquamarine and Diamond Ring

Aquamarine is a 7.5-8 on the Mohs hardness scale which means that it’s a fairly scratch resistant and durable stone making it a good choice for any jewelry. However, like all gemstones it can chip or crack if it’s hit hard. Most aquamarines on the market have been heat treated to remove yellow tints, resulting in a purer blue color. This is a permanent treatment that only affects the stone’s color. It’s durability makes Aquamarine ideal for carving as well, so it can be found as a Fantasy cut as well as the more traditional styles.

Fantasy cut Aquamarine

February’s Birthstone: Amethysts!

Wednesday, February 24th, 2010

oval amethyst

It’s pretty common knowledge that the birthstone for February is Amethyst… but why? In today’s society don’t most people associate February with Valentine’s Day, winter, snow perhaps? None of these associations speak purple to me, so why the Amethyst? Why not Rubies, red- the color of love?

Well, the history behind birthstones is a muddled one. There are actually a variety of birthstone charts out there, though it’s commonly believed that birthstones were originally linked to the Zodiac as opposed to the calendar year. Different stones were believed to resonate with different signs. The Amethyst was linked to Pisces, in late February.

Zodiac birthstones

Zodiac Birthstone Chart

So, despite our modern associations with the month of February, Amethysts as a stone for that time of the year predate even our modern calendar. Though, admittedly the current birthstone chart has undergone so many variations that the reason behind most of them is perhaps just that jewelers wanted to sell more of a particular gemstone…

amethyst ring with diamonds

Amethyst Ring

Since gemstones were first discovered and worn by the earliest peoples, they’ve been thought to have magical and medicinal properties. Amethysts were thought to bring stability, peace, balance, courage, and inner strength to its wearer. It was believed to cure withdrawal symptoms of any addiction, and cure headaches and insomnia. A magical little stone and, until the 19th century, extremely rare, it was used mostly in religious and royal crown jewelry. Which is why purple is considered such a royal color!

It was around the 18th century that birthstones became associated with months. Of course, throughout the years, the chart has changed again and again, but here is what most jewelers agree upon today.
Birthstone Chart

Amethysts are one of the most prized variety of quartz (one of the most common minerals on earth!). It was once considered to be of equal value to rubies, emeralds, and sapphires due to it’s scarcity. However, a large amethyst source was discovered in Brazil in the 19th century and since then Amethysts have been readily available across the globe, and for a pretty affordable price! Today, about 75% of commercial amethysts on the market were mined in South America.

Below is an image of what amethyst crystals typically look like before they’re fashioned into faceted or cabbed stones for jewelry. The color variation is very common and means that when the individual stones are cut out of the larger crystal, the cutter has to be careful about making a stone that appears uniform in color. It’s pretty good practice if you’re purchasing a loose amethyst to place it top (table) down on a white card to make sure your stone is uniform in color.

amethyst crystal

Amethyst Crystals

Amethysts have a whole range of color from pale lilac to a dark (almost black) purple. The most prized color is a vivid, medium dark purple with reddish flashes (hope that’s not too confusing- gemologists have a whole language all their own when discussing the colors of gemstones).  As with all gemstones, amethysts are graded after being cut- since most faceted amethysts on the market are “eyeclean” (no visible inclusions or fractures to the naked eye), most of what they’re being graded on is color. Here is a break down of the typical grades:

  • AAA: vivid, medium dark reddish purple or purple color with no visible face up color zoning
  • AA-A: slightly less saturated color with some face up color zoning
  • B: light lilac color (typical of mass market jewelry)
  • C: grayish, pale purple color

Though, as always, if you’re purchasing a gemstone what really matters is what appeals to you. The industry preferences aren’t as important as personal preferences!

The most common treatment for amethysts is heat. Usually a dark amethyst will be heated to lighten it. Sometimes amethysts will be heated to change their color to orange to create a citrine!

Got any questions about amethysts or other gemstones? Leave us a reply and our jewelers will get back to you (if we don’t know the answer- we’ll find it!).

Thanks for reading!!

Shopping for Diamonds: the 4 Cs

Tuesday, January 26th, 2010

diamond ring

In the 1940s and 50s, the Gemological Institute of America (GIA) developed an international grading system based on the 4 Cs: Carat, Color, Clarity, and Cut. These 4 characteristics taken in combination determine the value of a diamond.

carat weight

Carat is perhaps the most obvious value factor when it comes to diamond shopping. The bigger the diamond, the more it’s going to cost, right? The carat is the unit of weight for gemstones, and is usually rounded to the hundredth. Most of the diamonds used in jewelry weigh one carat or less. So here’s an inside tip on diamond shopping: think about purchasing a diamond that is slightly smaller than a full or half carat size. The price of a diamond increases greatly when they weigh in at these sizes so by looking at a diamond just slightly smaller than an even weight you’ll save a nice chunk of change without sacrificing anything in looks.

diamond color scale

Color.  The closer to colorless a diamond is, the more rare and valuable it is. Most diamonds have slight amounts of yellow or brown in their color. Most diamonds are graded on a scale developed by GIA and assigned a letter D-Z (the letters A-C are no longer used to avoid confusion or association with older grading systems).  The letter D represents a perfectly colorless diamond and each subsequent letter represents a specific range of color, ending with Z a near colorless diamond.

Clarity refers to the absence or presence of any inclusions or blemishes that were formed as the diamond itself was born- a sort of fingerprint that is unique to each diamond. Clarity is also graded on a scale, with diamonds falling anywhere in a range from Flawless to Included, dependant on how visible any inclusions are. This is the scale:

  • Flawless (FL) – No inclusions or blemishes are visible to a skilled grader using 10× magnification
  • Internally Flawless (IF) – No inclusions and only blemishes are visible to a skilled grader using 10× magnification
  • Very, Very Slightly Included (VVS1 and VVS2) – Inclusions are difficult for a skilled grader to see under 10× magnification
  • Very Slightly Included (VS1 and VS2) – Inclusions are clearly visible under 10× magnification but can be characterized as minor
  • Slightly Included (SI1 and SI2) – Inclusions are noticeable to a skilled grader using 10× magnification
  • Included (I1, I2, and I3) – Inclusions are obvious under 10× magnification and may affect transparency and brilliance

Cut. The most common cut for diamonds is the round brilliant, but there are many other fancy cuts that are also used: marquise, pear, oval, emerald cut, etc. The cut of a diamond affects its brilliance, fire, and sparkle. When grading a diamond’s cut, professionals look at the proportions, symmetry and the polish of the diamond.

Anytime you’re interested in a diamond for purchase, take into consideration these 4 value factors while making your decision. Jewelers should always provide you with the grades of the diamond, whether it’s set in a piece of jewelry or sold loose.