kenali permata anda - emerald/zamrud

      antara batu permata yang menajadi rebutan ramai dikalangan peminat batu permata ialah zamrud.
zamrud tergolong di dalam kumpulan mineral berryl. zamrud mempunyai warna hijau yang dihasilakan oleh kehadiran unsur chronium dan vandium. bermaksud perbezaan antara berryl dan zamrud ialah kehadiran kedua-dua unsur tersebut. mempunyai tahap kekerasan 7.5-8 pada ukuran mohs. Zamrud juga terkenal dengan sifatnya yang mempunyai inclusion atau rekahan yang banyak. oleh itu, batu ini dikategorikan sebagai fragile atau rapuh.
     bagaimana menilai harga batu zamrud?
     nilai dan harga permata zamrud ditentukan oleh 4 c, clarity, cut, crystal dan colour.
 1. crystal/water/gewe/air.  permata zamrud yang bernilai tinggi semestinya bersifat clear serta berair, tidak mempunyai inclusion yang keterlaluan. gemologist menggunakan ungkapan " a gem of a finest water" bagi merujuk kepada permata yang mempunyai air yang cantik atau gewe, clarity yang sempurna dan warna yang terang.
2. colour/warna. kepekatan warna hijau yang menyerlah akan menaikan nilai permata zamrud, namun perlu diingat, terdapat banyak permata beryl yang diwarnakan hijau dan didakwa sebagai permata zamrud. lebih teruk lagi di pasaran tempatan, terdapat colourless quartz atau batu quartz putih yang dicelup warna hijau.
terdapat juga apa yang dipanggil sebagai colour enhanced emerald iaitu zamrud yang ditambah warna.
3. clarity atau kejernihan yang dgredkan kepada opaque, tranparent, vvs dan beberapa kategori yang lain. apa yang disimpulkan, zmrud yang jernih, yang tiada inclusion banyak akan mempunyai nilai yang tinggi dipasaran.

huge raised controversy

Huge emerald digs up controversy

This 57,500-carat stone is being called the world’s largest cut emerald. It weighs 11.5 kilograms, or about 25 pounds.

Comment

By Michelle Graff

JAN 20, 2012

New York--Next week in Canada, an auction house is set to sell what is being touted as the world’s largest cut emerald, a commercial-quality, 57,500-carat behemoth mined in Brazil and purchased via the Internet from a dealer in India.

As the auction approaches, however, some gemologists are calling into question whether the stone is indeed an emerald or a piece of dyed white beryl.

The stone’s owner, a rare gems dealer from Calgary, Alberta, Canada, named Regan Reaney, said he purchased the stone from a dealer in India after a colleague there contacted him about it. After seeing some photos and having somebody in India verify it was “the real deal,” he purchased it through email, he said.

He refused to disclose the purchase price or the name of the dealer.

Since its purchase, Reaney said a total of three gemologists have examined the stone and determined it is a treated emerald.

The stone has been appraised at $1.15 million, and Reaney is certain it will achieve this price or more at auction. “We are confident it’s going to go into a bidding war,” he said.

One of the gemologists who examined the stone, Jeff Nechka, founder of Premier Gems in Calgary, said through testing, he was able to determine that he stone was a beryl that had been dyed green and clarity-enhanced through fracture filling.

The stone’s uneven tone, coupled with the fact that its inclusions are similar to what is found in an emerald formation, led him to determine it was an emerald. He notes, though, that to be 100 percent certain they would have to conduct “destructive testing,” essentially chiseling off a piece to examine the inside of the stone, a procedure the stone’s owner does not want to conduct.

As news reports about the 57,500-carat gem swirled this week, doubts began to surface about whether it indeed was a giant emerald or a more common, and less valuable, piece of white beryl that simply has been dyed green.

Shane McClure, director of West Coast identification services for the Gemological Institute of America’s laboratory, said while he has not seen this particular gem in person, the GIA avoids classifying dyed beryl as a particular gemstone in all cases, whether, for example, they are dyed green and look like an emerald or dyed pink and resemble morganite.

If the GIA were to examine this gemstone and determine it was dyed, it would be noted on the grading report, along with this comment: “The presence of dye prevents determining whether or not the stone would have sufficient depth of color to be considered emerald.” He adds that the lab would only include this comment if it could determine there was some natural green coloration present.

“If such a thing came into the laboratory and we determined it was dyed, there was no way we would call it an emerald,” he said.

Nechka, however, said that, to him, the uneven tones of the stone, which is lighter in some areas and darker in others, indicate that the gem is an emerald with its color enhanced by dye and not a piece of dyed white beryl, which would have even color throughout.

“I understand where they are coming from,” he said of the GIA. “They don’t want to take a stand on anything and be as neutral as possible.”

Another gemologist told The Calgary Herald that he bought a 23,000-carat “emerald” that the GIA later determined was a piece of dyed white beryl from the same dealer who sold Reaney the 57,500-carat gem. He also said he saw the big emerald for sale on eBay shortly before Reaney purchased it. 

McClure said while he is prohibited from talking about stones submitted by specific clients, they have seen large chunks of dyed white beryl in the lab, including one submission recently.

“These things do come through the lab, I can tell you that,” he said.

He recommends that whoever buys the stone obtain their own independent appraisal. “I hope that’s what happens in the end,” he said.

For his part, Reaney is standing by his massive emerald, dismissing the statements of both the GIA and the other gemologist, whom he said is just jealous he didn’t snatch up the stone.

“It is an emerald, 100 percent. They are welcome to fly up here and analyze it themselves,” he said of the GIA.