GemologyTidbits.com

Amethyst Sister to Citrine

mrahm — Fri, 03 Feb 2012 04:23:51 +0000

Did you know amethyst and citrine belong to the same gem species? Both amethyst and citrine are members of the mineral species, Quartz. The color is the most obvious difference between amethyst and citrine. Amethyst ranges in color from strong bluish-purple to purple to reddish purple, while citrine ranges in color from yellow to orange to brownish orange. Citrine shows very weak pleochroism while Amethyst shows weak to moderate pleochroism. Other quartz varieties include smoky quartz, rose quartz, green amethyst (actually green quartz), aventurine, tiger’s eye quartz and more.

Another major difference between amethyst and citrine is the fact that Amethyst is a type II gemstone, while citrine is a type I gemstone. Type I gemstones are usually eye-clean…those include citrine, aquamarine, green tourmaline, blue zircon and others while Type II stones generally show SOME eye-visible inclusions. Those include amethyst, alexandrite, sapphire, ruby, andalusite and others.

Both amethyst and citrine are common gemstones found in all types of gemstone jewelry and birthstone jewelry due to their availability and affordability.

Author: Michelle M. Rahm is a GIA-trained Graduate Gemologist and is President of Colorado’s Mile High Chapter of the GIA Alumni Association. She has been selling gemstones and jewelry online since 1997. Visit her websites JewelryImpressions.com and OurCustomWeddingRings.com

One Amazing Peridot

mrahm — Tue, 31 Jan 2012 22:13:25 +0000

This gorgeous green stone is an amazing peridot mined in Pakistan. It weighs a whopping 100.15 carats and has a price tag of $25,037.

Peridot with exceptional quality and color began to emerge from the mountains of Pakistan in the late 1990s. This amazing gem shows the superb color for peridot.

Peridot from the US is the most common peridot on the market and is generally commercial quality calibrated stones smaller than Pakistan peridot. Commercial quality peridot from the mines in Arizona is what you would normally see typical peridot jewelry such as birthstone jewelry and jewelry created for the mass market.

Peridot is one of the softer gems being 6.5 to 7 on the Mohs scale of hardness, therefore, it is not recommended for every day wear in jewelry pieces such as gemstone engagement rings, which seem to be gaining popularity once again.

You can find beautiful gems like this awesome peridot among others at our National Gem and Mineral Collection at the Smithsonian in Washington, DC

$308,000.00 and it’s not even a diamond?!

mrahm — Sat, 21 Jan 2012 19:36:24 +0000

This gorgeous green stone is smaller than a quarter, yet it’s worth more than a house…and it’s not even a diamond! This breathtaking stone is the world’s finest, largest Demantoid garnet from Russia with amazing intense green color and high dispersion (which makes it hard to take a good photo). The price tag of this stone, $308,000.00!

So why is this small stone so valuable? Demantoid garnets are generally quite small, in fact, anything over 1-2 carats is considered to be really huge. So this 11.24 carat stone is gigantic for a Russian demantoid.

Demantoid was discovered in the mid-1800s in the Western Urals and became very popular accent stones in high-end jewelry pieces. But production ceased during the Russian Revolution and demantoid fell out of popularity. In the late 1980s mining operations began once again with the reopening of the Soviet Union. The stone you see here is one of the stones that came out of the mine more recently.

You can find this piece among others at our National Gem and Mineral Collection at the Smithsonian in Washington, DC

A 25 Pound Emerald?

mrahm — Fri, 20 Jan 2012 19:14:07 +0000

This story caught my eye this morning so I thought I’d share it with you. A 25 pound faceted green beryl has surfaced and is going up for auction soon. It is being called the largest faceted emerald in the world. The controversy is whether or not this is truly an emerald or just a white beryl that has been dyed green.

Three gemologists have concluded the stone is a treated emerald, but one gemologist in particular determined that the stone is color treated and clarity enhanced through fracture filling.

The auction price is expected to top 1.15 million, but the controversy remains…for more info on the story visit: http://www.nationaljeweler.com/nj/colored-stones/a/~27692-Huge-emerald-digs-up-controversy

What’s The Center Stone?

mrahm — Thu, 19 Jan 2012 00:11:32 +0000

This interesting Harry Winston diamond brooch actually holds a 44.03 carat polished spherical diamond in the center.

Although the diamond is not gem quality, the special polished spherical shape makes this diamond jewelry piece unique. While diamonds normally have adamantine luster, this particular stone looks almost vitreous (oily) on the outside.

Find this and other interesting treasures at our National Gem and Mineral Collection at the Smithsonian in Washington DC.

This Amazing Aquamarine…

mrahm — Tue, 10 Jan 2012 16:41:53 +0000

I hope everyone had a blessed holiday season. I wish you prosperity and good health for the new year.

I mentioned in a previous post that I have the privilege of touring the gem and mineral collection at the Smithsonian recently. This year I plan to share that experience with you by showing you some of the most amazing things I saw. Most of these treasures were back in the vault rather than out on display, so it was a blessing to be able to see them. Many will be on display soon.

This amazing aquamarine from Minas Gerais, Brazil is oval step cut. It weighs a whopping 310.04 carats. Aquamarine is from the gem species, Beryl, which is the same species as emerald.

Tangerine Tango: The Fashion Color For 2012

mrahm — Thu, 08 Dec 2011 16:24:17 +0000

Sarah Bernard of The Thread just released the new fashion color for 2012: Tangerine Tango. While she doesn’t mention any gemstone jewelry that might offer a great way for you to accessorize in style, consider stylish jewelry made with padparadschas or orange sapphires, fire opal, malaya or spessartite garnets, imperial or orange topaz, and more.

The image above shows a Chatham-created padparadscha orange sapphire in front, a fire opal in the upper left and a spessartite garnet to the right.

I mentioned in a previous post that we have been experiencing increased sales of orange sapphire engagement rings. The news today is encouraging that this trend will continue. Tangerine Tango, here we come!

A planet made of diamond?

mrahm — Wed, 07 Dec 2011 21:21:48 +0000

Wow, how exciting. Scientists have discovered a new planet made of diamond, sounds too good to be true, doesn’t it? Apparently because the new planet is so dense and consists largely of carbon, scientists figure the carbon must be in crystalline form, which is essentially diamond. How cool is that?

See the story here:
http://www.foxnews.com/scitech/2011/08/29/astronomers-discover-planet-made-diamond/?intcmp=obinsite

Affordable Diamond Alternatives

mrahm — Fri, 02 Dec 2011 02:47:34 +0000

So many of our customers are either green-minded, budget conscious or conflict-conscious and no amount of pursuasion will change their minds…they simply do not want a diamond as the center stone in their engagement ring. For this reason, we’ve prepared a video to help consumers educate themselves about and compare popular diamond alternatives. Of course, we’ve taken the opportunity to show a phenomenal 1.12 ct. D color Internally Flawless ideal cut diamond while we’re at it. Take a look…

We offer Chatham-created white sapphire engagement rings as well as moissanite engagement rings on our custom rings website.

Crystal Shapes

mrahm — Thu, 01 Dec 2011 05:49:19 +0000

Sometimes faceted gemstones from different species can look so similar to each other that it’s difficult to tell them apart. It’s much easier to tell gemstone species apart in the crystal form because different species form in different crystal systems…and show particular crystal shapes.

Quartz is a mineral species that forms in the hexagonal (trigonal) crystal system while topaz is a minerals species that forms in the orthorhombic crystal system. Can you tell which of these crystals is a topaz and which is the quartz?

Both of these specimens are on display in the Gem & Mineral Collection at the Smithsonian in Washington DC. The upper left hand photo captures one of the finest large topaz crystals. It weighs 111 pounds and was mined in the Minas Gerais area of Brazil. The bubble-like inclusions are really imprints of albite crystals that once grew against the back surfaces. The smaller crystal to the right is a quartz crystal, also from the Minas Gerais area of Brazil…not quite as large as the topaz crystal. Can you see the distinct difference in the shape of the crystals? Knowing how different mineral species form is key in identifying them.

Repairing an 850 Carat Imperial Topaz

mrahm — Tue, 29 Nov 2011 03:24:29 +0000

Because November is topaz month, I thought this would be a fun project to share with you.

I’ve prepared the video below showing the step-by-step process of repairing a chipped table facet on a large 850 carat Imperial Topaz. My friend, Denton Anderson of GemCutting.com, is a world-renowned gem cutter who worked on this amazing stone. All the raw video and photos were provided by Denton, I just made it a little more fun. Enjoy!

Happy Thanksgiving

mrahm — Thu, 24 Nov 2011 20:03:22 +0000

As I sit here smelling the turkey in the oven and imagining the feast that awaits us in a couple of hours, I think of how grateful I am for so many things in my life. I have been blessed in so many ways.

My wish for you this Thanksgiving is that you ponder all the wonderful things in your life, enjoy the day with the ones you love and give thanks for the blessings in your life. Life is full of lots of wonderful gifts, sometimes we just have to look for them.

Thanksgiving blessings to you today!

Citrine and Topaz Durability

mrahm — Mon, 21 Nov 2011 04:34:37 +0000

I mentioned previously that golden topaz was harder than citrine and more costly. But there is more to a gemstone’s durability than just hardness, which is a gemstone’s ability to resist scratches. Toughness, which refers to a gemstones resistance to chipping, cracking and breaking, is an important consideration as well.

While topaz is harder than citrine, it has a poor toughness. In other words, dropping the stone or even a light blow to the stone could cause it to break. Citrine has a good toughness, but only ranks a 7 on the scale of 1-10 for hardness, so it is not recommended for every day wear.

In our business, lots of customers are looking for birthstone engagement rings and other gemstone engagement rings. Obviously, an engagement ring is meant for every day wear, so you need a stone that is durable. A suitable alternative to both citrine and golden topaz to put in an engagement ring would be yellow sapphire. Yellow sapphire is a 9 on the Moh’s scale of hardness and has excellent toughness. Many shades of yellow sapphire, such as that in the yellow sapphire engagement ring you see here, are similar to common shades of citrine and yellow topaz.

Citrine Sister To Amethyst

mrahm — Wed, 16 Nov 2011 04:23:25 +0000

Did you know citrine and amethyst belong to the same gem species? Both citrine and amethyst are members of the mineral species, Quartz. The color is the most obvious difference between citrine and amethyst. Citrine ranges in color from yellow to orange to brownish orange, while amethyst ranges in color from strong bluish-purple to purple to reddish purple. Citrine shows very weak pleochroism while Amethyst shows weak to moderate pleochroism. Other quartz varieties include smoky quartz, rose quartz, green amethyst (actually green quartz), aventurine, tiger’s eye quartz and more.

Another major difference between citrine and amethyst is the fact that Amethyst is a type II gemstone, while citrine is a type I gemstone. Type I gemstones are usually eye-clean…those include citrine, aquamarine, green tourmaline, blue zircon and others while Type II stones generally show SOME eye-visible inclusions. Those include amethyst, alexandrite, sapphire, ruby, andalusite and others.

Both amethyst and citrine are common gemstones found in all types of gemstone jewelry and birthstone jewelry due to their availability and affordability.

National Gem Collection

mrahm — Mon, 14 Nov 2011 20:58:38 +0000

I had a great time touring the National Gem & Mineral Collection at the Smithsonian today with the Curator, Jeff Post. Starting January 1st, I’ll take a break from birthstone tidbits and share with you some fascinating info about various different pieces in our National Gem Collection.

Happy Veteran’s Day

mrahm — Fri, 11 Nov 2011 14:06:24 +0000

It is with heartfelt thanks that I write today to address the men and women of our armed forces. Your sacrifice and bravery is appreciated more than words can say. You put your lives on the line to keep our country safe and to uphold the freedom of our great nation.

It is with great respect and admiration that I wish you a Happy Veteran’s Day…may your day be special.

November Birthstones: Citrine & Golden Topaz

mrahm — Thu, 10 Nov 2011 22:06:07 +0000

There are two birthstones generally recognized as birthstones for November: Citrine and Golden Topaz. Citrine is the orangish yellow variety of quartz, while golden topaz is the yellowish golden variety of topaz.

While golden topaz is a harder than citrine (8 on the Moh’s scale of hardness vs. a 7 for Citrine), citrine is less expensive and more plentiful in a variety of shapes and sizes, thus, of the two, citrine is the more common gemstone found in birthstone jewelry.

In addition to being November’s birthstones, citrine is the recognized gift for the 13th anniversary and golden topaz is the recognized gift for the 23rd anniversary.

Tourmaline

mrahm — Wed, 09 Nov 2011 15:04:59 +0000

My plan for the end of October was to tell you a bit about tourmaline and show you some orange sapphire engagement rings in honor of Halloween. However, my father was unexpectedly admitted to the hospital and I was out of town dealing with that. He’s out now and doing well, thankfully. So I’m back in the office. I will be spending a few days catching up, then I’ll move into November information.

Pink tourmaline shares the honor of being October’s birthstone with opal. Tourmaline comes in every color of the rainbow, but generally pink tourmaline is considered the October birthstone.

For centuries tourmalines have adorned the jewels of royalty. The Empress Dowager Tz’u Hsi, the last empress of China, valued the rich pink colors above all other gemstones. The people of ancient Ceylon called tourmaline “turmali,” the Sinhalese word for “more colors.” Perhaps this is why ancient mystics believed tourmaline could encourage artistic intuition: it has the palette to express every mood.

Vivid reds, hot pinks, verdant greens and blues abound in this marvelous gem variety. Earth tones as varied as a prairie sunset are readily available. Not only does tourmaline occur in a spectacular range of colors, but it also combines those colors in a single gemstone called “bi-color” or “parti-color” tourmaline. One color combination with a pink center and a green outer rim is called “watermelon” tourmaline, and is cut in thin slices similar to its namesake.

Dark blue, blue-green, and green tourmalines are occasionally heated to lighten their color. Red tourmalines, also known as rubellites, and pink varieties are sometimes heated or irradiated to improve their colors. Heat and irradiation color enhancement of tourmalines is permanent.

Occasionally, some tourmalines may have surface-breaking fissures that are filled with resins, with or without hardeners. Care must be observed with these gemstones. Avoid exposing them to harsh abrasives and strong chemical solvents.

Information: Provided by the American Gem Trad Association
Author: Michelle M. Rahm is a GIA-trained Graduate Gemologist and is President of Colorado’s Mile High Chapter of the GIA Alumni Association. She has been selling gemstones and jewelry online since 1997. Visit her websites JewelryImpressions.com and OurCustomWeddingRings.com

Caring for Opals

mrahm — Sat, 22 Oct 2011 02:39:42 +0000

Opals, with or without enhancement, should be treated tender loving care as it ranges in hardness from 5-6.5 on the Mohs scale. Opal is softer than many other gemstones and should be stored carefully to avoid being scratched by other jewelry. It should also be protected from blows, as exposed corners can chip. Opal should not be exposed to heat or acid, or extreme temperature changes and air pressure changes. For this reason, the best way to clean opals is with a soft, damp cloth or soft damp toothbrush. Avoid using strong or abrasive cleaners.

Over time, opals can develop a network of tiny fissures, called ‘crazing’. For this reason, some gemologists recommend storing opals or opal jewelry in a damp environment or, especially for loose opals, submerged in water to protect them from crazing.

These amazing opal specimens from Rainbow Ridge in Virgin Valley, Nevada are stored in water-filled glass cases to protect them from crazing.

Information: Provided by the American Gem Trad Association Author: Michelle M. Rahm is a GIA-trained Graduate Gemologist and is President of Colorado’s Mile High Chapter of the GIA Alumni Association. She has been selling gemstones and jewelry online since 1997. Visit her websites JewelryImpressions.com and OurCustomWeddingRings.com

Opal Enhancements

mrahm — Fri, 21 Oct 2011 13:54:13 +0000

Opals are often enhanced to improve their appearance and durability. Opals can be treated by a variety of methods to bring out their play of color. The two most common treatments are Sugar Treatment and Smoke Treatment. For either of these treatments to work effectively, the opal must be fairly porous.

For the sugar method, the white, gray, or black opals are immersed in a sugar solution and then in strong sulfuric acid, which carbonizes with the sugar and leaves microscopic carbon specks that blacken the body color, making its flashes of color more visible.

For the smoke method, opals are wrapped in paper before they are heated and smoked so particles of soot penetrate the opals surface, giving it a darker background color and enhancing the play of color.

Other opal treatments include permeation with colorless oil, wax, resin, plastic, and hardeners to improve their appearance and durability, which includes masking the appearance of crazing. Occasionally, some thinner or translucent opal may be painted with a black epoxy on the backside of the gemstone to darken the body color and improve the play of color.

Fire opal is not commonly enhanced.

Michelle M. Rahm is a GIA-trained Graduate Gemologist and is President of Colorado’s Mile High Chapter of the GIA Alumni Association. She has been selling gemstones and jewelry online since 1997. Visit her websites JewelryImpressions.com and OurCustomWeddingRings.com