The Green Sand Beach

There are four green sand beaches on Earth.  One of them, Papakolea Beach, is at the southern tip of the Big Island of Hawaii.  And I was lucky enough to go there this January, during my 2-week vacation in the Hawaiian Islands.  (Side note:  If you ever get the chance to go to Hawaii, TAKE IT!)   This beach isn’t easy to get to, as it’s about two and a half miles from the dirt parking lot.  Your choices are a “shuttle” which is actually an old van or pick-up truck for $15, or a good 45 minute walk.  Both choices leave you dusty and thirsty, as you make your way towards an amazing oasis.  

The Green Sand Beach

Why is the sand GREEN?  Well, the answer lies under the crust of the Earth, in the upper mantle, where one of the dominant rocks is Peridotite.  The name may remind you of August’s birthstone, Peridot, whose color is a yellowish to brownish green.  Peridotite is brought to the surface on the waves of magma that erupt from the same volcanos that formed the Hawaiian Islands.  It’s made primarily of the mineral, Olivine, which has a much higher melting temperature than most minerals.  So, the magma brings it to the surface, surrounds it with lava rock (basalt), but doesn’t melt it into the mixture.  These peridotite xenoliths eventually reveal themselves as erosion breaks down the basalt host rock.  

What happens next is what happens to every rock, given time and exposure to the elements.  The peridotite breaks into smaller and smaller pieces, until it’s a bunch of tiny olivine grains.  But these little grains are heavier than most sand, so if the conditions are protected enough, they have a tendency to stay.  And if enough of them stay in one place, it makes the beach look green.  Conditions are rarely as perfect as here in this bay, cut by the ocean into the side of a former cinder cone.  

So, how does it feel to play on a beach of green gems?  The truth is, most peridotite is not gem quality, and grains of sand are way too small to be valuable.  But there is something special, at least to this gemologist, about having tiny peridot between your toes.   It was great building a sand castle out of what the Hawaiians call their Hawaiian Diamonds.

The sand is protected by the state, so you’re not allowed to fill a container with it unless you are a native Hawaiian.  But, wouldn’t you know, the driver of my shuttle was a twelfth generation Hawaiian, and he was trying to impress the young, pretty woman sitting next to him.  He gave her a handful of green sand, mixed with larger peridot pebbles, in an empty water bottle.  When she showed them to me, I gasped in delight.  “Oh, my gosh!” I exclaimed.  “They’re beautiful!!”

When she found out I worked with gemstones, she secretly gave me the water bottle, saying, “You’ll appreciate it so much more than I will.”  So, I have my special little stash of green sand which I will keep forever!

Hawaiian Diamonds (aka The Tears of Pele–Goddess of Volcanos)

 

History of Birthstones

garnet

Garnet: January birthstone

Most of my life I’ve wished I was born a few days earlier, mainly because my birthstone would be an emerald instead of pearl or alexandrite.  When it came time to buy my high school class ring, I chose the emerald green stone rather than the pale purple one.  When my husband and I designed our 30-year anniversary ring, we designed it with an emerald for the center stone, even though pearl is the traditional gift for the 30-year anniversary.  As you can see, I’ve always just gone with what I wanted rather than what I was ‘supposed’ to want.  But my decisions got me to thinking about the origin of birthstones.  Who deemed that each month be represented by a different gemstone?  When was this decision made?  And why?

My research on these questions has revealed an interesting and somewhat nonsensical journey.  Most sources say that the idea of birthstones started with the Bible and Aaron’s breastplate.  Aaron had 12 stones in his breastplate, representing the 12 tribes of Israel.  No one knows for sure what the 12 stones were, but chances are high that they were pretty rocks, like jasper or lapis.  These are rocks that were native to the area.

A first century historian named Josephus supposedly made the numeric connection between the 12 stones and the 12 months of the year.  For centuries the idea was to have 12 stones, carrying a different one each month.  They weren’t really birthstones because they weren’t associated with the owner’s birth.  They were associated with months of the year.  The individual stones were supposed to bring good luck and good health during each one’s specific month.

But somewhere along the way, the idea changed.  Experts say that between the 15th and 18th centuries, people began to see themselves as having one stone, corresponding to the month of their birth, that would bring them good fortune.  These stones, with a few exceptions, are very different from the birthstones of today.  Have you ever heard of bloodstone?  It’s an opaque green stone with red spots.  It was the birthstone for March.  How about sardonyx?  That’s a banded, rusty brown-colored, translucent chalcedony that was the birthstone for August.

Bloodstone: March birthstone

Bloodstone: March birthstone

Sardonyx: August birthstone

Sardonyx: August birthstone

 

 

 

 

 

 

In 1912, Jewelers of America, an association with a definite interest in marketing gemstones, sought to standardize the list.  The official list of birthstones had garnet, amethyst, aquamarine, diamond, emerald, pearl, ruby, peridot, sapphire, opal, topaz (the orange-yellow-brown kind), and turquoise.  Some of the months had two birthstones, partly in deference to the traditional stones.  So March had aquamarine AND bloodstone.  August had peridot AND sardonyx.  But, let’s face it, if you were born in March, which gem would you rather have?  A transparent medium blue one or an opaque dark green one with red blemishes?  It didn’t take long to drop these traditional choices.

The 1912 list has had few changes in the last 100+ years.  In 1952, alexandrite was added as a birthstone for June and citrine was added as a birthstone for November.  December’s traditional birthstone of lapis lazuli was replaced with blue zircon.  In 2002, tanzanite, the blue-purple gemstone that had been discovered in 1967, was added to the list for December.  And, most recently, in 2016, spinel was added as a birthstone for August.

Why the additions?  Many people would say it’s a marketing move.  Birthstones aren’t really seen as bringing good luck or good health anymore.   They don’t have the significance they used to have.  They’re just fun.  So why not have more choices?  I’m really happy for all you August babies who no longer feel confined to the yellowish-green of peridot.  Spinel offers great variety! (See my blog on spinel–July 28, 2016).

So, what do we make of this idea of birthstones?  To me it sounds like a complicated game of Telephone.  Do you remember that game when someone whispers a phrase to someone else, and it goes around the circle?  The final uttering of the phrase bears no resemblance to the original.  That’s how I feel birthstones came to be.  From Aaron’s breastplate to the writings of Josephus to the Jewelers’ list, it’s a crazy, convoluted path. But this is where we are and what we have.  My suggestion?  Adopt your favorite gemstone, the one that has meaning to you,  and make it YOUR birthstone.

amethyst

Amethyst: February birthstone

The New Birthstone- August’s Spinel

 

Natural Spinel

Natural Spinel

I have some very good news for all of you born in August.  Just recently, the American Gem Trade Association and Jewelers of America announced that SPINEL has been added to the birthstone list as an alternative to peridot.  Not everyone is a fan of peridot’s yellowish-green color, and the gem stone has a narrow range of hue.  Spinel, on the other hand, comes in almost every color of the rainbow!  The most prized color is red.  Pink and blue are two other popular hues.  So, because spinel is a relatively unknown gemstone and because changes to the birthstone list don’t happen often, it seemed important to write about it.

Peridot

Peridot

Many people have never heard of spinel.  It was recognized as a separate mineral about 200 years ago, but, until then, red spinel was often mistaken for ruby.  Some famous gems, like the Black Prince’s Ruby, which is set in England’s Imperial State Crown, are actually red spinel.  Those who have heard of it often associate it with something “cheap” or “common.”  Synthetic (aka man-made) spinel has been used for years to make the stones for high school class rings because it’s inexpensive to produce in lots of different colors that mimic birthstones like emerald, ruby, and sapphire.  Synthetic spinel is also used as the top, bottom, or both of a “triplet” that substitutes for a natural gemstone.

Natural spinel is a beautiful mineral made of magnesium, aluminum, and oxygen.  It’s colorless unless a trace element such as chromium, iron, or cobalt makes its way into the recipe.  Chromium leads to a pink or red spinel.  Iron and cobalt lead to violet and blue spinels.  A combination of trace elements produces orange or purple spinels.  These colors need no enhancement, so spinel is rarely heat-treated or irradiated.  It’s a fairly hard gemstone, scoring 8 on the Mohs Scale, and it forms in the cubic crystal system.  These qualities mean that spinel is hard enough to take a good polish and easy enough to cut and facet.  And the gem is usually eye-clean when it comes to inclusions.

Spinel is traditionally associated with Asia–especially Myanmar, Vietnam, and Sri Lanka.  More recently deposits have been found in Tanzania and Madagascar.  Large crystals are quite rare, so the value goes up exponentially, not only for great color but also for size.  While not as expensive as fine ruby or pink sapphire, natural spinel is not an inexpensive gem.  Red spinel would cost approximately 30% of the cost of a similarly sized ruby.  And pink spinel would be about 85% of the cost of a same size pink sapphire.  It’s not easy to find spinel in a jewelry store.  Maybe that will change now that it’s a birthstone, but, up until now, it’s been more of a collector’s stone.

So, take heart all of you who longed for another birthstone! It’s spinel to the rescue!!  Ask your jewelry store for a peek at its spinel.  Here’s a peek at ours.

1.28 carat pink spinel

1.28 carat pink spinel