Šis ir otrais raksts no sērijas par ieguldījumiem dārglietās lasītajam saprotamajā valodā. Pieredzējis diamantaire, Gabriel Levin-Cafrir, stāstīs par dārgakmeņiem, kas var tikt sajaukti ar dimantiem (daži no tiem ir dimantu simulanti). Lai nekļūdītos - lasiet, pētiet, ziniet!

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Gabriel Levin-Cafrir (M.Soc.Sci), second generation diamantaire, graduate of the Center of Gemological Studies under the leadership of one of the leading Graduate Gemologists of Israel - Eli Dori, specialization - Diamond Expert (“Diamond Grading & Evaluating” diploma), at Diamond Exchange, Ramat Gan, Israel. The evaluation of diamonds is based on the G.I.A (Gemological Institute of America) standards. Practiced in Israeli commpany “Keren Or”. Works in jewellery and gemstones sales sphere (family business), consults, does lecturing.

Passion investing in jewellery. Part II: gems, not diamonds

Before we go deeper into what actually a diamond is, I see a necessity to clarify what gem we will talk about exactly later on.

In this article we will speak about some gems that can be confused with diamonds by hearing their names (some of them are in the category of diamond simulants, but we will return to this problem separately in one of the upcoming articles).

In my practice I have met different man-made names of gems, like “morning diamond” etc. From my point of view the most confused gem names are:

1. Demantoid
2. Eastern diamond
3. Herkimer diamond

A bit confused? So was I, but only at the beginning…Let’s start by the given order.

“Demantoid”

Especially if you pronounce it like „dimantoid” - sounds almost the same as „diamond” (diamant, dimant), right? Maybe the majority of people will know the difference, but i met some that got confused and couldn’t see the difference between diamonds and demantoids.

Demantoid is...... a garnet, specificaly saying - one of it’s variety that has green colour.

Generally speaking there are more than twenty garnet categories, called species (every specie has it’s own colour or colour spectrum), but only five garnet species are commercially important as gems. Those five are:

1. pyrope – red;
2. almandine (also called almandite) – from purple to red;
3. spessartine - orange and yellow;
4. grossular (grossularite) - have the widest range, from colorless through yellow to reddish orange and orangy red, as well as a strong vibrant green called tsavorite, plus a few rare garnets even change color under different types of light;
5. andradite - yellow and green.

(https://www.gia.edu/garnet-description; https://4cs.gia.edu/en-us/blog/garnet-buying-guide/)

The sixth, uvarovite, is also a green garnet that usually occurs as crystals too small to cut. Many garnets are chemical mixtures of two or more garnet species. (https://www.gia.edu/garnet-description; https://4cs.gia.edu/en-us/blog/garnet-buying-guide/)

But let’s get back to demantoid. Demantoid means “diamond-like” and not without a reason. The name comes from the Dutch and makes reference to the outstanding quality of this gem, its incomparable brilliance and fire. Its high spellbinding dispersion (flashes of spectral colors refracted back from the stone) is also remarkable. The demantoid is a master of splitting the light and breaking it down into all the colours of the rainbow and does it even better than the diamond. (https://web.archive.org/web/20080624171321/http://www.gemstone.org/gem-by-gem/english/demantoid.html).

 

It has these parameters :

Mineral: Garnet group (a family of closely related mineral species)

Species: Andradite (one of several important species of gem garnets)

Variety: Demantoid (the green variety of the species andradite)

Chemistry: Ca₃Fe₂(SiO₄)₃

Refractive index: 1.880 to 1.889

Birefringence: None

Specific gravity: 3.82-3.88

Mohs harness: 6.5-7

Birthstone: January

(https://www.gia.edu/garnet/gem-overview; https://www.gia.edu/garnet-description; https://web.archive.org/web/20080624171321/http://www.gemstone.org/gem-by-gem/english/demantoid.html; https://www.ajsgem.com/gemstone-information/demantoid-garnet-37.html; https://www.gemsociety.org/article/demantoid/)

Demantoid has its vivid green colour – chromium is the cause. Because the gem ranges in many shades of green from yellowish or brownish green with a golden glow to a very rare intense green hue it rivals the beauty – and price – of emerald (particularly precious is a deep emerald green, though this only occurs very rarely indeed). (https://4cs.gia.edu/en-us/blog/gia-green-gemstones-buying-guide/)

Demantoid is also the only green gem that can have “horsetail” inclusions: radiating bundles of mineral fibers(usually made of two minerals: a tiny opaque crystal that is the focal point, and golden brown crystal threads of chrysotile, which flares out from the centre of the stone, creating the appearance of a horsetail). Because of that the gem had always been able to be identified through the microscope. These delicate wisps can increase the value of the gem. “Horsetail” had previously occurred in almost all demantoids (they become much desired gemstone in Russia after been found in 1868 in Ural mountains and was the main source of gems), but they were missing in the relatively inclusion-free gems from Namibia (was found there in the middle of the 1990s – main source of gems nowadays). Because of that the horstail inclusion became desirable and as a result many collectors are willing to pay a higher price for it and if you see it, then you definitely can say, that the gem is from Russia and it costs much more.

(https://web.archive.org/web/20080624171321/http://www.gemstone.org/gem-by-gem/english/demantoid.html; https://4cs.gia.edu/en-us/blog/gia-green-gemstones-buying-guide/) (https://web.archive.org/web/20080624171321/http://www.gemstone.org/gem-by-gem/english/demantoid.html; https://4cs.gia.edu/en-us/blog/gia-green-gemstones-buying-guide/)

Some believe the true value of the garnet is its power to bring the wearer good health, wealth and happiness. According to Indian astrology, garnet helps eliminate negative feelings (depression, guilt) and instill greater self-confidence and mental clarity to promote creative thinking and peace of mind. In ancient and medieval times, gems like garnet were also thought to be remedies for inflammatory diseases and to soothe the angry heart. https://www.gia.edu/birthstones/january-birthstones

Garnet is not the hardest of gemstones, so the safest way to care for a garnet is to clean it with warm and soapy water. Ultrasonic cleaning is usually safe unless the garnet has inclusions. Steam cleaning this gemstone is risky and not advised. (https://4cs.gia.edu/en-us/blog/the-various-minerals-of-garnet/)

Demantoid is the most expensive kind of garnet and one of the most precious of all gemstones. (https://www.gia.edu/gems-gemology/spring-2015-gemnews-fine-corundum-demantoid-garnet; https://www.gia.edu/garnet-quality-factor)

 

“Eastern diamond”

You will be surprised (or not), but eastern diamond actualy are...... leucosapphire - that is how those who follows ancient traditions call it.

Sapphire is a variety of the mineral corundum, also known as mono-crystalline aluminum oxide. The mineral corundum is composed only of aluminum and oxygen, and it requires a growth environment that’s free of silicon. However, silicon is a very common element, making natural corundum relatively uncommon.

Sapphire is one of the three jewellry colored precious gemstones - the other two are ruby and emerald. Diamonds and pearls are also precious gemstones, but they are considered as separate categories. For example, in gemology there are three main kind of gemstone courses that you can learn: diamonds, coloured stones and pearls (and yes, pearls are classified as gemstone).

 

It has these parameters:

Mineral: Corundum

Chemistry: Al₂O₃

Refractive index: 1.762 to 1.770

Birefringence: 0.008 to 0.010

Specific gravity: 4.00

Mohs Hardness: 9

Birthstone: September

https://www.gia.edu/sapphire

 

Actually the name “sapphire” can also apply to any corundum that’s colour is not red and doesn’t qualify as ruby (ruby can only be within red hues), which is another corundum variety (in total there are two main corundum gemstones used in jewellery: sapphire and ruby). It can assume a rainbow array of colors given the correct trace impurities and growth conditions. In addition to blue, corundum also includes “fancy” sapphires of every other color (including colorless). The major fancy sapphire color categories are padparadscha, pink and purple, orange and yellow, green, intermediate hues, gray, black, brown and colourless. There are also “parti-colored” sapphires that show combinations of different colors. Some stones exhibit the phenomenon known as color change, most often going from blue in daylight or fluorescent lighting to purple under incandescent light. Each category has its own color range, causes of color, and market. https://www.gia.edu/sapphire-quality-factor

Leucosapphire is the transparent colorless type of a sapphire and they are often inaccurately called “white sapphire”. Truly colorless sapphire is quite uncommon, and most “colorless” sapphire is actually near-colorless, with traces of gray, yellow, brown, or blue colour (by the way, in its purest state, corundum is actually colorless). (https://www.gia.edu/doc/The-Separation-of-Natural-from-Synthetic-Colorless-Sapphire;https://kamneteka.com/leykosapfir-zamenitel-almaza/amp/; https://mineralcatalog.com.ua/mineralleikosapfir-bescvetnyi-sapfir-white-sapphirecolorless-sapph#spec;https://dic.academic.ru/dic.nsf/ruwiki/1004911; https://o-prirode.ru/lejkosapfir/;https://finesell.ru/vse-kamni/lejkosapfir.html; https://www.gia.edu/sapphire-description)

Colourless sapphire brings wisdom and strength of spirit. It carries an extremely pure energy for clarity of thought and opening the powers of the mind. It strengthens communication with the Higher Self level of consciousness in seeking spiritual guidance for this lifetime, and brings the resolve needed to overcome obstacles to one’s spiritual path. It is beneficial in revealing one’s talents and potential, and inspires living with integrity and keeping true to one’s ideals when faced with difficult choices or circumstances. Wearing colourless sapphire enhances the qualities of fairness, objectivity, morality, and freedom from greed. It also assists in breaking self-defeating habits or behaviours that impedes spiritual progress. It also bestows the people who wear it, particularly in marriage, and gives the people abundant happiness, carries pure energy to balance your soul and mind. Colorless sapphires is associated with the forty-fifth wedding anniversary. (https://www.gemsngems.com/product-category/natural-gemstones/natural-white-sapphire/; https://kamneteka.com/leykosapfir-zamenitel-almaza/amp/; https://mineralcatalog.com.ua/mineralleikosapfir-bescvetnyi-sapfir-white-sapphirecolorless-sapph#spec; https://dic.academic.ru/dic.nsf/ruwiki/1004911)

Thanks to it’s hardness, You have to put a lot of effort to mechanicaly damage leuco sapphires (but still don’t try it). To clean sapphire jewelry, use a lukewarm solution of water and mild dishwashing soap, or one part ammonia to six parts water. Gently brush the sapphires with a small bristle brush, especially underneath the stones where dirt collects. Rinse and dry. (https://www.shaneco.com/jewelry-education/product-guide-101;  https://finesell.ru/vse-kamni/lejkosapfir.html)

Colorless sapphires were once popular diamond imitations, and they’ve staged a comeback as accent stones in recent years. Still, now you rather find moisannite or cubiz zirconium as a diamond immitator then lecuosapphire.

 

“Herkimer diamond”

First time i met “Herkimer diamonds” was during my searching through internet market platforms (as eBay, Amazon and etc.). First thought was “Oh, what an interesting name for a diamond! Maybe they mean the location where the diamond was found?”, then I saw the price tag (it was so cheap, almost a joke) and I thought "Is it possible that they started to sell industrial-quality diamonds?!” I opened the picture of a piece of jewellery and saw a very clean gemstone. So I started to collect information about this stones and, as you may have guessed, again it wasn’t diamonds..

 

So, “Herkimer diamond” is a double-terminated quartz crystal discovered within exposed outcrops of dolostone in and around Herkimer County, New York and the Mohawk River Valley (these crystals were first discovered in New York, Crystal Grove Diamond Mine, St. Johnsville). Because the first discovery sites were in the village of Middleville and in the city of Little Falls, respectively, the crystal is also known as a Middleville diamond or a Little Falls diamond. (http://www.geologyin.com/2015/11/what-type-of-quartz-is-considered-as.html)

The geological history of Herkimer diamonds is an intriguing one that begins at the bottom of a shallow sea about 495 million years ago. The bedrock in which the quartz crystal are found began forming approximately half a billion years ago in a shallow Cambrian Sea that lapped against the southern shores of the ancestral Adirondack Mountains.  The sediments (calcium magnesium carbonate) which slowly accumulated beneath the sea’s salty waters were gradually compacted under the weight of thousands of feet of additional sediments, forming the rock strata Dolostone.  While still beneath the sea, water seeped through the pores of the rock often creating “vugs” by dissolving part of the rock. Geologists theorize that these crystals extremely slowly formed in this small solution cavities. There are also larger cavities that are several feet in diameter that are called "pockets".The material that would later form the crystals was deposited as a waxy organic material along with quartz sand and masses of pyrite. All of this was encased in a rock made up of two carbonate minerals: dolomite and calcite. Sediments slowly buried the rock and its temperature rose. As a result, molecules that had been holding quartz dissolved from the sand in solution were broken apart by thermal splitting. This caused the quartz to come out of solution very slowly and resulted in the growth of quartz crystals of exceptional clarity. (Michael R. Walter). The crystals are magnificent works of nature, found in the rock, having a diamond-like geometrical shape.  (http://www.geologyin.com/2015/11/what-type-of-quartz-is-considered-as.html; https://www.herkimerdiamond.com/frequently-asked-questions/; http://www.therussianstone.com/articles/2017/08/09/10-facts-about-herkimer-diamonds/;

https://geology.com/articles/herkimer-diamonds.shtml)

Herkimer diamonds are found cloudy, smoky or even containing a variety of rare impurities, but most of them are brilliant, water-clear crystals show the classic 18-sided, doubly terminated hexagonal form (result of the crystals growing with very little or no contact with their host rock, they are doubly terminated). Impurities (rare and general) can include clusters, scepters, fluid inclusions (sometimes incorrectly called enhydros), phantom, and bridge crystals. (https://www.herkimerdiamond.com/frequently-asked-questions/;https://geology.com/articles/herkimer-diamonds.shtml)

Inclusions that provide clues to the origins of the Herkimer diamonds are solids (hydrocarbon materials are the most common; they range from small eye-visible particles down to micron-size particles, which, when abundant, can impart a smoky color to the crystals), liquids (salt water or petroleum), and gases (most common carbon dioxide).  Some crystals contain anthraxolite or decayed plant life.  The anthraxolite resembles bits of black coal within the crystals.  A special discovery would be an enhydro crystal.  These special specimen are crystals that contain a water bubble within it.  An extremely lucky find is an enhydro which contains species of anthraxolite floating in the water bubble.  Twins, double, clusters, tabulars, smokies, skeletals, and phantom crystals are all valuable specimen found in pockets. A fluid inclusion is a pocket within a crystal containing liquid, usually water, sometimes also methane or oil, and rarely, smaller crystals. A phantom is a crystal containing other visible crystals of the same type, a skeletal crystal contains a series of crystal edge outlines inside the crystal and a hopper crystal has its faces replaced by a step like pattern. Calcite, dolomite, pyrite, sphalerite and quartz (often in the form of tiny Herkimer Diamonds) are typical  mineral inclusions. (https://www.herkimerdiamond.com/frequently-asked-questions/;https://geology.com/articles/herkimer-diamonds.shtml; https://herkimerdiamond.com/frequently-asked-questions/)

To be  a perfect Herkimer diamond is not just about clarity but about form. Crystals commonly occur intertwined or clustered and often tiny, perfect crystals are attached to the backs of larger ones. Herkimer Diamond quartz crystals falls at a 7.5 on the Mohs scale. Range of color of Herkimer diamonds : clear, white, smoky, champagne, golden and golden-red. (https://therussianstone.com/articles/2017/08/09/10-facts-about-herkimer-diamonds)

Because many of the New York crystals are known for their extreme clarity, Wiccan and New Age belief systems often ascribe specific occult properties and a wide variety of mystical powers to them. The Herkimer Diamonds of New York are not a recent discovery. The Mohawk Indians knew about the crystals. They found them in stream sediments and plowed fields. These people were amazed with the crystals and immediately held them in high esteem. They used the crystals as amulets, used them to make tools, and traded them with other tribes. They began to lose interest in the crystals when European glass beads began to arrive in the early 1600s. (https://geology.com/articles/herkimer-diamonds.shtml)

Although Herkimer County, New York is the location for which these crystals are named, similar doubly terminated quartz crystals have been found in many other locations, including Hungary, France, Italy, Canada, Pakistan, China and others. They have the same appearance but cannot rightfully be called "Herkimers." (https://geology.com/articles/herkimer-diamonds.shtml)

As you can see, our ancestors, tried to compare gemstones to diamonds by giving them names related to this beautiful eternal stone what makes diamond a very unique precious gemstone. Nowadays we have a lot of information but not all of it is true, so my piece of advice is that if you are not sure what you hear or see or were told about, don’t be shy and ask for a full description. It is better for you to ask twice rather make a mistake that will cost you money. Don’t rush, investigate!