ABOUT DIAMOND
With exceptional beauty , lustre , and sparkle ,diamond is the most iconic of all
precious stones and highly prized in jewelry all over the world. However this is only one of its uses.
Industrial diamond is a vital component in oil drilling, specialist scalpels , tool manufacturing , and many other industries , all of which use the supreme hardness of diamonds for cutting tools and
abrasive powders. There is no firm boundary between gem-grade and industrial - grade diamonds - around 80per cent of the diamonds mined each year are unsuitable for gemstone wear , and find other uses in industry. However , very small or lower - grade stones can be polished into gemstones rather than being used in industry.
Discovering diamonds
For over 2,000 years, diamonds were found only as crystals in river gravels, and, until 1725, India was the major source. As Indian production waned, diamonds were discovered in Brazil, and in 1867 they were found in gravels neat the Orange River in the Kimberley region of South Africa. Further exploration there revealed volcanic pipes of a previously unknown rock type containing diamonds; this was named kimberlite and was recognized as the diamond source rock. Its discovery formed the basis of the modern diamond industry. Many similar pipes have since been found in other African countries, Siberia, Australia, and more recently in Canada, China, and the USA.
ダイヤモンドの発見
2000年以上もの間、ダイヤモンドは川砂利に交じる結晶としてしか発見されず、1725年まではインドが主な産地だった。インドでも産出が減少すると、ブラジルで発見されるようになり、さらに1867年には南アフリカのキンバリー地域にあるオレンジ川の砂利の中でダイヤモンドが見つかった。その後の調査で、これまでは知られていなかった岩石からなる漏斗状火道（マグマの通り道）にダイヤモンドが含まれていることがわかった。この火成岩はキンバーライトと名付けられ、ダイヤモンドの根源岩とされた、この発見により現代のダイヤモンド産業が築かれた。それ以降は同様の火成岩が他のアフリカ諸国やシベリア、オーストラリアで見つかり、さらに最近ではカナダ、中国、アメリカでも見つかっています。
Carat
Refers to the weight of a diamond.
Carat is often confused with size even thought it is actually a measure of weight. One carat is equivalent to 200milligrams.One carat can also be divided into 100 "points". A.75 carat diamond is the same as a 75-points or 3/4 carat diamond.
A 1-carat diamond costs exactly twice the price of a half-carat diamond,right? Wrong.
Since larger diamonds are found less frequently in nature,which places them at the rarest level of the diamond quality pyramid, a
1-carat diamond will cost more than twice a 1/2-carat diamond(assuming color,clarity,and cut remain constant).
Cut and mounting can make a diamond appear large (or smaller)then it's actual weight. So shop around and talk to your jeweller to find the right diamond and setting to optimize the beauty of your stone.
カラット（重さ）
「○○カラットの大きなダイヤモンド」という言葉を耳にしたことがあると思いますが、カラットは、「大きさ」ではなく「重さ」を表す単位です。1カラット=0.2グラムで重くなればなるほど希少価値
高くなります。
カラットは、「＿＿ct」と表示され、1ct＝0.200gで、1gは5ctとなります。
電子デジタルの天秤を用いて千分の1カラットまで正確に測定し、少数第3位を8捨9入、もしくは第3位まで表示します。
原石の大部分は1ct未満の小さなものばかりですので、大粒の原石は、とても稀少です。
カットするとさらに小さくなることも考えると、大きければ大きいほどその価値は上がっていきます。
CUT
Refers to the angles and proportions of a diamond.
Based on scientific formulas, a well-cut diamond will internally reflect light from one mirror-like facet to another and disperse and reflect it through the top of the stone. This results in a display of brilliance and fire, thereby placing well-cut diamonds higher on the Diamond Quality Pyramid than deep or shallow-cut diamonds. Diamonds that are cut too deep or too shallow lose or leak light through the side or bottom, resulting in less brilliance and ultimately, value.
Cut also refers to shape - round, square, pear, or heart for example. Since a round diamond is symmetrical and capable of reflecting nearly all the light that enters, it is the most brilliant of all diamond shapes and follows specific proportional guidelines.
Ask a jeweller to find out more about these guidelines.
Non-round shapes, also known as "fancy shapes",will have their own guidelines to be considered well-cut.
カット（プロポーション）
ダイヤモンドは、ただ格好良くカットすればいいわけではありません。カットのプロポーションや角度が良くなければ、輝きを存分に発揮することはできません。
他の３つ要素がダイヤモンドが生まれつき持つものであることに対して、カットは人の手で加えられる要素となります。
職人の技によって、そのダイヤモンドが持つ良さを引き出し、輝けるかどうかが決まります。
CLARITY
Refers to the presence of inclusions in a diamond.
Inclusions are natural identifying characteristics such as minerals or fractures,appearing while diamonds are formed in the earth. They may look like tiny crystals,clouds or feathers.
To view inclusions, jewellers use a magnifying loupe. This tool allows jewelers to see a diamond at 10x it's actual size so that inclusions are easier to see. The position of inclusions can affect the value of a diamond
There are very few flawless diamonds found in nature, thus these diamonds are much more valuable.
Inclusions are ranked on a scale of perfection, known as clarity, which was established by the Gemological Institute of America(GIA).
The clarity scale, ranging from F(Flawless) to Included(I), is based on the visibility of inclusions at a magnification of 10x.
Some inclusions can be hidden by a mounting, thus having little effect on the beauty of a diamond. An inclusion in the middle or top of a diamond could impact the dispersion of light, sometimes making the diamond less brilliant.
The greater a diamonds clarity, the more brilliant, valuable and rare it is -and the higher it is on the Diamond Quality pyramid.
クラリティ （透明度）
クラリティは、「透明度」を表す基準です。キズ・欠け、内包物（インクルージョン）の大きさ・場所・性質などを鑑定して評価が決まります。包有物が多いと透明度が下がり、その分輝きを損なってしまうので、透明度が高いほど評価も高くなります。
COLOUR
Refers to the degree to which a diamond is colorless.
Diamonds range in colour from icy winter whites to warm summer whites.
Diamonds are graded on a colour scale established by the Gemological Institute of America(GIA)
which ranges from D(colorless)to Z.
Warmer colored diamonds(K-Z) are particularly desirable when set in yellow gold.
Icy winter whites(D-J) look stunning set in white gold or platinum.
Colour differences are very subtle and it is very difficult to see the difference between,
say, an E and an F. Therefore,Colour are graded under controlled lighting conditions
and are compared to a master set for accuracy.
Truly colorless stones, graded D, treasured for their rarity, are highest on the
Diamond Quality Pyramid. Colour, however, ultimately comes down to personal taste.
Ask a jeweler to show you a variety of colour grades next to one another to help you determine your colour preference.
カラー （色）
ダイヤモンドは無色透明ではなく、実際にはかすかに色がついているものがほとんどで、無色透明なものほど高く評価されます。
ダイヤモンドの色が黄色になればなる程、希少性がさがります。しかし、ある一程の黄色味を超えると、ファンシーカラーという評価がされ、他の基準でグレーディングされます。ファンシーカラーは他にも赤、ピンク、青、緑があります。