Tag: Gem

What’s tougher than a diamond? You’ll never guess!

Our recent gemstone spotlight, featuring Jade, inspired us to dig a little deeper into what exactly the Mohs Hardness Scale is, and also the difference between hardness and toughness. Jade is a very tough stone, but not a very hard stone. In ancient times, it was used to create weapons and other tools, yet only falls between 6 and 7 on the Mohs scale.
How could that be? The answer is that toughness and hardness are not the same. Hardness (which is measured on the Mohs scale) determines how easily a mineral can be scratched, while toughness judges its ability to withstand breakage, as from a fall or impact with another object.

A guide to the Mohs scale

While the Mohs Scale consists of a numerical scale of 1-10, the toughness scale is a little less specific. There is not yet a standardized test for measuring toughness, and minerals are graded on a scale of Exceptional, Excellent, Good, Fair, or Poor.

Diamonds, which are commonly known as the hardest natural mineral, sit at a solid 10 on the Mohs scale. However, they only rank as far as “Good” on the toughness scale. Jade, however, ranks as “Exceptional” and is therefore considered to be tougher than a diamond, although it sits at a 6-7 on the Mohs scale. GemSociety.org uses the comparison of wood vs. glass to help you remember the difference between toughness and hardness. Glass is very hard and can easily scratch wood, but wood is very tough, so if you bang a piece of glass and a piece of wood together the glass is more likely to be broken by the piece of wood.

With this logic, diamonds can easily scratch jade, but what happens if you whack a piece of jadeite and a piece of diamond together? The diamond could crack, but your jade will probably come away a little bruised, but not too much worse for the wear. Now you know!

 

Sources:
https://www.gemsociety.org/article/gemstones-tough-hard/
http://www.firemountaingems.com/resources/encyclobeadia/charts/68ag
http://geology.com/minerals/mohs-hardness-scale.shtml

 


Gemstone Spotlight: Sapphire, September’s Protection

“A maiden born when autumn leaves 
Are rustling in September’s breeze, 
A sapphire on her brow should bind 
`Twill cure diseases of the mind.”

-Gregorian Birthstone Poem

Some examples of sapphire color variation.
Some examples of sapphire color variation.

Those born in September call the sapphire their own. Sapphires, the sister stone to the ruby (which is really a red sapphire), are the the second hardest gemstone, rivaled only by the diamond. Corundum (a.k.a. the mineral that makes up rubies and sapphires) comes in every color of the rainbow. Many colors are shown in the photo above. Aside from the traditional blue, popular colors include pink, yellow, and green, like the pendant below.

Green Sapphire and CZ Pendant in Sterling Silver

It is most commonly seen in shades of blue, blue-green, and blue-violet. The most prized varieties are a rich, intense shade of blue that is not too light or too dark. The best sapphires are said to come from Sri Lanka and Madagascar, although sapphires are found in many other places around the world, including Thailand, Australia, the U.S. and China.

A high quality sapphire
A high quality sapphire is deep blue in color.

Wearing a sapphire is said to protect your loved ones from harm. If you are a Taurus, wearing sapphires has been said to cure and protect against mental illnesses, which is implied in the Gregorian Birthstone Poem at the top of this blog. It is also said to help cure rheumatism, work as an anti-depressant, promote clairvoyance, and aid in astral projection, to name a few traits. Since the middle ages, sapphires have been a popular stone amongst priests and royalty. Clergymen from medieval times wore blue sapphires to symbolize Heaven, and commoners thought the stone itself attracted heavenly blessings.  Sapphire stones were regarded as a talisman to ward off evil. Star sapphires were said to be so powerful that they would continue to protect the wearer as it was passed on to someone else, and was used primarily as a protective stone for travelers. Another legend says a venomous snake encased in a container made of sapphire would die. It represents faithfulness and sincerity in relationships, and symbolizes peace, joy, and wisdom. Metaphysically, it is a great stone for healing and protective purposes, and for mental growth.

A star sapphire
A star sapphire.

Thinking of giving a sapphire as a gift? Your September girl will be blown away! Sapphires (along with rubies) are also popular in engagement rings due to their superb hardness (Prince William gave a sapphire to Kate Middleton for their engagement!). Because of the amazing variety of colors they come in, you could even pick a stone in her favorite color. She will love you for being so thoughtful.

Think also of giving them as a 5th, 23rd, or 45th wedding anniversary present. Star sapphires are a traditional gift for a 65th wedding anniversary as well.

sources: almanac.com, gemselect.com, americangemsociety.org, www.bernardine.com/gemstones/sapphire

Gemstone Spotlight: The Pearl! June’s Treasure

“Who comes with summer to this earth
And owes to June her hour of birth
A pearl should wear against her skin
Who’s innocence many a heart shall win.”

– Gregorian Birthstone Poem

Pearls in an oyster.
Pearls of various colors in an oyster shell.

Could you guess which month is our favorite? The birthstone for June is the pearl! Other accepted stones are alexandrite and moonstone, but when you can claim pearls as your gem why would you want another option?! We at Pearls International are always excited for a chance to talk about pearls. June girls are lucky to have such a unique gem to call their own. Pearls are so special because they are the only gem that is produced by a living organism. They are perfect from the moment they leave the shell, requiring no polishing, faceting, or other enhancements, and you will never find two pearls that are perfectly identical. If you are a fan of our site, you’ll know they come in a huge variety of colors, shapes, and sizes! Pearls are found all over the world, with most freshwater pearls coming from China and Japan. Many saltwater pearls are also found in Japan, and are commonly farmed in the Tahitian islands and Australia as well.

The history and mythology of the pearl is another part of what makes them so unique, special, and interesting. Almost all pearls today are cultured, which means an irritant has been placed into a mollusk by a human and the pearl has formed around that irritant. This process was developed around the 1920s. Before cultured pearls, the only pearl jewelry was made from pearls found in an oyster by chance. Only about one in 10,000 oysters will produce a gem quality pearl by itself, so as you can imagine, a strand of natural pearls would have been very, very expensive back then. In fact, did you know a strand of pearls once paid for an entire house? It sounds too crazy to be true, but it is. Pearls really are legendary. Legends around their origins formed from a variety of cultures around the world. The Chinese believed the gem to have formed inside the brains of dragons, while other cultures thought they were formed when oysters swallowed drops of moonlight. The Greeks thought they were drops of water flung from Aphrodite’s body when she was born from the sea.

Illustration of a Chinese dragon with pearlq
The Chinese once believed that pearls were formed inside the brains of dragons and sometimes dropped into the sea when the dragons fought.

Pearls are a symbol of innocence, purity, and love. Giving a bride pearls on her wedding day has been said to prevent tears. Looking for the perfect pearl gift for your June girl? Pearls International has the best pearl rings, necklaces, bracelets, and more! Also consider pearls as a gift for a 30th wedding anniversary.

Black freshwater pearl and crystal hoop earrings
These gorgeous black pearl and crystal hope earrings are sure to make an impression.

18" graduated freshwater pearl necklace in white
Want a more traditional gift? We offer lots of classic white strands.