Diamonds & Diamond Value Flashcards
What are Value Factors?
features used to judge the quality and value of all gemstones.
What is a diamond?
鑽石是什麼？
Diamond is a mineral made of a single element: Carbon
鑽石是地底下碳元素的結晶
what are the 4 C’s?
Clarity 淨度
Color 色度
Cut 切工/ 車工
Carat 克拉重量
Value factors that describe the quality of a finished diamond.
What is the percentage of carbon in a diamond?
- 95%
0. 05% can be one or more trace elements - influences shape & color.
What are the formation conditions of a diamond?
High temperature and high pressure conditions, existing only within a specific depth range beneath the earth’s surface.
What color are most diamonds?
Yellow, and brown. Colourless diamonds are extremely rare and valuable.
What are Inclusions?
Clarity characteristics totally enclosed in a polished gemstone or extending into it from the surface.
What are blemishes?
Clarity characteristics confined to the surface of a polished gemstone.
What are Clarity characteristics?
The collective term for inclusions and blemishes.
How can a diamond cutter increase the value of a diamond rough?
By cutting away undesirable clarity characteristics.
What are the positive effects of clarity characteristics?
- they help geologists separate diamond from stimulants. Inclusions in diamonds often have a different appearance from inclusions in stimulants.
- as no two clarity characterists are the same, they help identify individual stones.
- they provide scientists with valuable information on how diamonds form.
Which clarity characteristic would have more impact on a stone’s beauty and value?
Inclusions.
Blemishes are easier to remove and to increase in value - recutting/repolishing
Inclusions close to surface can be removed but results in reduction in diamond’s weight.
What is the top grade in the GiA clarity grading system?
最高級淨度是什麼？
Flawless. No visible inclusions or blemishes when examined under 10-power (10x) magnification.
無瑕級。完全不見「淨度特徵」
What are some of the rarest colours of diamonds?
鑽石最稀有的有哪些顏色？
Red, purple, and green.
What is Synthetic Gem?
A man made gem with essentially the same chemical composition, crystal structure, and properties as a natural gem.
What is a Simulant? / Imitation?
A natural or man made material that resembles a gem.
What is the difference between Synthetics and Simulants?
Synthetics diamonds contain carbon atoms. They are arranged the same way in both natural and synthetic diamonds.
Simulants/imitations only look like natural gems. Ie. glass, zircon, colourless synthetic spinel. YAG ( yttrium aluminum garnet) GGG (gadolinium gallium garnet), CZ synthetic cubic zirconia
What is brilliance?
亮光
The brightness created by the combination of all the white light reflections from the surface and the inside of a polished diamond.
亮光乃是由鑽石表面及內部所有反射出的白光總和， 也是已切磨鑽石只所以明亮的原因。
What is fire?
火光
The flashes of color you see in a polished diamond.
火光是鑽石散發出的七彩顏色光線。
What is scintillation?
散光是鑽石，光源或者觀察者移動時所產生的閃動光。
The flashes of light you see when the diamond, the light, or the observer moves.
What is the top part of the gem above the girdle called?
Crown
冠部
What is the narrow section of a finished gem that forms the boundary between the crown and the pavilion called.
Also functions as the gem’s setting edge?
Girdle.
腰圍
What is a diamond’s pavilion?
底部
The lower part of a faceted gem below the girdle.
What is a diamond’s facet?
刻面
A flat, polished surface on a finished gem.
What is a culet?
底尖
Small facet at the bottom of a finished gem.
How can a diamond’s cut affect it’s quality?
A well cut diamond will display brilliance, fire, and scintillation.
一雙工藝精巧的手能夠充分突顯其光彩，折射出鑽石深藏的閃亮光芒。車工細緻的
How many facets does a standard round brilliant diamond have?
33 facets above the girdle, and 24 or 25 below the girdle, depending on whether or not there’s a culet.
What is a brilliant cut? 明亮式切磨
General term for gems of any shape with facets that are mostly triangular, or kite shaped, and that radiates from the centre.
Which is the most popular diamond cut?
Standard round brilliant
明亮式
Very small round diamonds are sometimes fashioned as which type of cut?
Single cut. With 17 or 18 facets.
It has a table, 8 crown facets, 8 pavilion facets, and sometimes a culet.
What are cuts in other shapes other than round called? What are some of them called?
Fancy cut. 花式切磨
Marquise 馬眼形 Princess 公主方形 Oval 橢圓形 Heart 心形 Emerald 祖母綠形 Pear 梨形 Radiant 雷地恩形
What is a step cut? 階梯式
Fancy cut. “Steps” usually consists of 3 rows of four sided facets that are parallel to the girdle on the crown and pavilion.
Emerald cut is the most popular step cut with 57/58 facets
What is a baguette cut?
A small, four-sided step cut that’s rectangular, square, or tapered.
What is a mixed cut?
Cut that combines brilliant-cut and step-cut styles
What is a branded cut?
Cutting style that’s developed, named, and promoted by a specific manufacturer.
What is a metric carat? And how much does it weight in grams?
The international unit of measurement for gem weight.
One carat equals 1/5 of a gram (0.200g)
What is the advantage of a brilliant cut and a step cut?
Brilliant cuts generally show more fire than step cuts.
Step cuts usually show color better.
How much is a Point in terms of carat?
How many points in a carat?
One hundredth of a carat (0.01ct)
One carat = 100 points
How many carats in an ounce?
142 carats -
1.00 ct = 0.200 g = 0.007 oz
What is a gem’s durability? 堅固度
A gem’s ability to withstand wear, heat and chemicals.
Durability consists of 3 properties:
• Hardness 硬度
• toughness 韌度
• stability 安定度
What is a diamond’s hardness? 硬度
How well a gemstone resists scratches and abrasion.
物質抵抗被刮丶磨的能力
What is a diamond’s Toughness? 韌度
Toughness means resistance breaking, chipping, or cracking - how we’ll a stone can survive impact from a fall or a blow.
物質，寳石抵抗破壞裂或斷裂的能力
What is the ratio of diamond to ore?
0.30 ct of rough diamond per metric ton of ore.
Mine workers have to process about a ton of rock to recover less than half a carat of rough diamond.
What is Gem Quality?
Rough gem material that requires normal processing to produce a polished gem suitable for use in jewelry.
What is Near-gem quality?
Rough gem material that requires substantially more processing than gem-quality rough to produce a polished gem suitable for use in jewelry.
What is Industrial quality?
Rough gem material that is suitable for use in tools, abrasives, and other industrial applications.
Industrial quality diamonds make up the bulk of rough recovered from many mines.
Why are diamonds so expensive?
Because they are rare and costly to mine.
What does the stability of diamond’s refer to? 安定度
It describes how well the diamond resists chemical and temperature changes. 掋抗光丶熱和酸鹼等化學物的能力
Which scale rates the relative hardness of gems and minerals? How many are on this scale?
The Mohs Scale. 10 minerals
What do Lazare, Hearts on Fire, and Ekati diamonds have in common?
They are all part of the branded diamond market
What is thermal shock?
Damage caused by sudden, extreme temperature changes, creating new fractures and cleavages or causing existing ones to spread.
Which part of the diamond is it’s weakest? Which shapes are more prone to breakage?
Diamonds are weakest where the atoms are farthest apart. Aka it’s cleavage direction.
The points of pears and Marquise are vulnerable if not covered by prongs.
What happens to a burned diamond?
They look white and cloudy. Repolishing is fairly easy and is the only way to restore without losing much weight.
