Saturday, February 9, 2013

Rare Alexandrite Specimen

Alexandrite Specimen
High quality alexandrite specimen weighing 41.11 cts, from Tanzania. This specimen will cut several large alexandrites, hence the relatively high value.

Chrysoberyl crystalizes in the orthorhombic system and is often found as flat prismatic crystals. Some crystals, like the pictured alexandrite from Tanzania are twinned and known as trillings, where the crystals inter grow and form flowers or cyclic twins that give the false appearance of hexagonal symmetry. Another feature is the stepped growth lines which are clearly visible on the surface of the crystal.

Thursday, January 31, 2013

Natural alexandrite vs Synthetic alexandrite

Synthetic vs Natural Alexandrite
Synthetic Alexandrite vs Natural Alexandrite




Many gemstones described as synthetic alexandrite are actually synthetic corundum laced with vanadium to produce the color change. This alexandrite like sapphire material has been around for almost 100 years. The material shows a characteristic purple-mauve color change which although attractive, does not really look like alexandrite because there is never any green. The stones are very clean and may be available in large sizes. Gemological testing will reveal a refractive index of 1.759 - 1.778 (corundum) instead of 1.741 - 1.760 (chrysoberyl). Under magnification, gas bubbles and curved stria may be evident. When examined with a spectroscope a strong vanadium absorption line at 475nm will be apparent.

Flux grown alexandrite is more difficult to identify because the inclusions of undissolved flux can look like natural inclusions. Alexandrite grown by the flux-melt process will contain particles of flux, resembling liquid feathers with a refractive index and specific gravity exactly the same as natural alexandrite. Layers of dust-like particles parallel to the seed plate, and strong banding or growth lines may also be apparent. Stones may contain groups of parallel negative crystals, flux inclusions, triangular metallic platelets, or gas bubbles. Flux grown alexandrites are more difficult to spot because the colors are convincing and because they are not clean. These stones are expensive to make and are grown in platinum crucibles and crystals of platinum may still be evident in the cut stones

Generally, the size and the clarity of a stone are important clues in the determination its formation. Since large clean alexandrites are so rare in nature, it is unlikely that a large stone offered for a few dollars in a pawn shop, on a beach, or on a street corner by a native seller could ever be a  natural alexandrite. Although large stones cannot be discounted altogether, any large gem represented as a natural alexandrite should be examined by an experienced gemologist or tested in a lab.


Thursday, January 17, 2013

Top 5 Alexandrite Rings

Alexandrite is an excellent gemstone for an engagement ring, but it can be expensive and really hard to find.Fine stones usually run into thousands of dollars per carat and genuine alexandrite jewelry is almost always custom work. 

Alexandrite ring
Alexandrite ring - Engagement
Alexandrite ring
Alexandrite ring - Enternity
Alexandrite ring
Alexandrite ring - Vintage
Alexandrite ring
Alexandrite ring  - Contemporary
Alexandrite ring
Alexandrite ring - Classic

Sunday, December 30, 2012

An alexandrite engagement ring Q&A

David Wein Alexandrite Jewelry Making
David Wein Alexandrite Jewelry Making

Peter:  Alexandrite, is it a good stone for an engagement ring?

Lora:  Natural alexandrite is extremely rare, valuable, collectable and an exciting gemstone with a rich heritage and an exotic feature of changing colour. It also represents the birthstone for June.  Alexandrite is a remarkable gemstone featuring all the qualities needed for a perfect engagement or wedding ring: rarity, beauty, durability and history.

I cannot imagine any other stone in my engagement ring. It is the only gem, which has a real nobility and exclusivity feel to it, regardless of the quality (you need to spend a fortune on a top range sapphire or diamond to have this feel).

Peter:  How expensive is the real alexandrite?

Lora:  It is very important to note, that alexandrite value is based on it's quality and size. It means that a mediocre alexandrite can easily sell for less than a fine diamond or sapphire of the same size. Poor quality alexandrite may be found for as little as $300.00 a carat, but decent quality alexandrites, with strong colour change, under 1 carat size  fetch between $3.000 to $15.000 per carat.

Most alexandrite gemstones used for engagementr rings are under one carat, and it is safe to budget $1.500  to $6.000 for an 18K gold engagement ring, with  0.3-0.6cts alexandrite in the center and some diamonds around it.

Peter:  How to buy  alexandrite engagement ring?

Lora: Try  to see a real stone in person at a high-street jeweller first before committing to it, because the colour change feature is very delicate and most people or first time buyers expect too much. However, if the colour change strength is not your main requirement, and you understand that the stone will look greenish in the daylight and purplish in the candlelight, you are ok.  Only a very rare and astronomically expensive stone will be green or red without a spotlight.

Also make sure, that you buy your alexandrite ring from a reputable jeweler. You should always ask for the stone certificate as well as receipt of payment. Stone certificate may cost you little more money but it will provide you a  peace of mind knowing that you are getting  genuine natural alexandrite.

Peter:  Where to buy  alexandrite engagement ring?

Lora: Although it would be next to impossible to find a natural alexandrite piece of  jewelry in your average jewelry shop in the UK or USA,  there are  few safe options:

You can buy  loose alexandrite gemstone from a  gem dealer and ask your jeweller to set it for you or  you can buy or order a bespoke alexandrite jewellery piece from a jewellery brand specialising in it: Mark Henry or David Wein

Peter:  What about Chatham, Verneuil  or Cultured alexandrite?

Lora:  Some antique, estate and vintage jewelry sellers, as well as eBay, Amazon and other online sellers are misleading their customers on purpose or by ignorance  by using the "Verneuil", "Chatham" or "Cultured" designation to describe synthetic alexandrite or synthetic corundum laced with vanadium.

Use of the "Verneuil Alexandrite", "Chatham Alexandrite" or "Cultured Alexandrite" term in the context of a description for sales without including the "lab created" or "synthetic" prefix, is incorrect and deliberately misleading. These stones will show a range of color changes and are usually very clean and available in large sizes but they are synthetic and their resale value is zero.
Synthetic alexandrite may cost up to  $100.00 per carat on a retail level, but it has no resale, investment or emotional value.

And most synthetic alexandrite is not even lab created alexandrites, but synthetic corundum laced with vanadium. True synthetic alexandrite is actually a rarity because it is much easier to create synthetic corundum and synthetic spinel with color change properties that look like alexandrite.

Personally, I would never accept an engagement ring with a synthetic stone in it. Call me prude, but if the stone is fake, so is the proposal and the whole thing is a sham. If money is an issue, there are many alternatives with lower quality, but natural coloured gemstones or diamonds.

David Wein Alexandrite Ring
David Wein  Alexandrite Ring "Valeria"

 


Wednesday, September 19, 2012

Exquisite alexandrite engagement rings

David Wein Alexandrite Rings

 "Look, here it is, the prophetic Russian stone! O crafty Siberian. It was always green as hope and only toward evening was it suffused with blood..."
 

Alexandrite is the stone of duality. Green or red, good luck or misfortune, the significance is interpretive and related to the social and historical context of the time and the culture. Forever changing its colors, alexandrite is a magical gemstone with universal appeal that continues to fascinate and be admired by astrologers, scientists, and gem lovers throughout the world.

Alexandrite is an excellent gemstone for an engagement ring, but it can be expensive and really hard to find. Fine stones usually run into thousands of dollars per carat and genuine alexandrite jewelry is almost always custom work.




Monday, October 18, 2010

Mystery behind the chatoyant gemstone


"Chatoyance" is French for cat's-eye. When impurity minerals occur in fibers, they give gemstones a silky appearance. When the fibers line up along one of the crystalline axes, a stone can be cut to display a bright reflective line—a special effect called cat's-eye.

Pictured cat's eye chrysoberyl is also known as cymophane. The name being derived from the Greek words cyma and phanes, meaning “wave” and “appearance.” Microscopic needle-like inclusions inside the stone reflect a streak of light known as the cat’s eye.

The cat's eye’s inclusions are aligned parallel to the crystallographic axis and they are always cut as cabochons with the fibrous need-like inclusions running across the narrow part of the stone as this is the only way to display the effect properly.

Saturday, September 18, 2010

Alexandrite like phenomenal color change Garnet


Color change garnet is one of the most rare, interesting, and phenomenal of all gemstones. The color change can be intense and equal to the color change of top quality alexandrite and fine color change garnets can easily be mistaken for alexandrite. Some of the best stones are from the deposit in Bekily, Southern Madagascar. Stones from this mine are well known for their strong alexandrite like color change.

Change of color is not the same as the changes in color with crystal orientation that affects tourmaline and iolite, which are due to the optical property called pleochroism. Only rare tourmalines, garnets and alexandrite absorb certain wavelengths of light so strongly that in sunlight and indoor light they appear different colors.