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Gemmology > Chapter 16 > Flashcards

Chapter 16 Flashcards

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1
Q

What is a laboratory-grown diamond?

A

A manufactured diamond with essentially the same physical, chemical, and optical properties as natural diamond.

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2
Q

List alternative terms for ‘laboratory-grown diamond’.

A
  • Lab-grown
  • Synthetic
  • Lab-created
  • Manmade
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3
Q

Who regulates the terminology used to describe lab-grown diamonds in the United States?

A

The Federal Trade Commission (FTC).

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4
Q

What does ‘natural’ refer to in the context of diamonds?

A

A diamond that originated or grew in the earth and was mined.

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5
Q

True or False: Laboratory-grown diamonds have different optical properties than natural diamonds.

A

False.

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6
Q

Fill in the blank: The FTC regulates which terms are acceptable and which are _______ to describe lab-grown diamonds.

A

deceitful

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7
Q

What are the two major commercial technologies used to produce lab-grown diamonds?

A

High-pressure, high-temperature (HPHT) method and chemical vapor deposition (CVD) method

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8
Q

When did the HPHT and CVD methods evolve?

A

Over the past 75 years

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9
Q

What was the initial purpose of the HPHT and CVD methods?

A

To produce diamonds for industrial purposes

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10
Q

What significant advancement did Smithson Tennant make in 1797?

A

Proved that diamond is a very dense form of pure carbon

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11
Q

What inspired researchers to explore creating diamonds from carbon?

A

The abundance of carbon

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12
Q

What technological limitations did researchers face in the 1800s and early 1900s?

A

Inability to produce the high levels of heat and pressure needed for diamond formation

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13
Q

Who was hired by General Electric Corporation in 1941 to design a laboratory for diamond production?

A

Percy W. Bridgman

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14
Q

What recognition did Percy W. Bridgman receive for his work in 1946?

A

Nobel Prize in Physics

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15
Q

What method did William G. Eversole use to create tiny synthetic diamonds in 1952?

A

Chemical vapor deposition (CVD) method

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16
Q

When did GE scientists create their first batch of industrial diamonds using the HPHT method?

A

December 1954

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17
Q

What year did GE announce their achievement of producing diamonds using the HPHT method?

A

1955

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18
Q

Which company had successfully produced diamonds with the HPHT method in 1953 before GE?

A

Swedish company ASEA

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19
Q

When did GE begin marketing synthetic diamond grit produced with the HPHT method?

A

Late 1957

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20
Q

How long did GE keep the diamond production process confidential under federal regulations?

A

Two years

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21
Q

What year did GE file worldwide patents for their diamond synthesis process?

22
Q

Who followed GE in patenting diamond synthesis?

23
Q

What was the main challenge in creating large gem-quality diamonds?

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A

Increasing crystal size while controlling quality

Larger crystals take much longer to form than smaller ones, making production challenging.

24
Q

In what year did the GE research team produce the first cuttable gem-quality HPHT lab-grown diamonds?

Study These Flashcards
A

1970

These diamonds weighed about 1 carat each in rough form.

25
What was the range of carat weights for fashioned stones cut from the first HPHT diamonds?
0.26 to 0.46 ct. ## Footnote The color of these diamonds ranged from F to J.
26
What was the highest clarity rating achieved for the first HPHT diamonds?
VS ## Footnote Despite this, commercial production was not economically feasible.
27
Which companies began producing larger, near-colorless HPHT diamonds in the 1990s?
Sumitomo Electric Industries, GE, and De Beers ## Footnote These diamonds were primarily marketed for high-tech applications.
28
What was the primary color of the HPHT diamonds produced by Russian firms in the 1990s?
Yellow ## Footnote These stones were small and had poor clarity.
29
What was the weight of the largest reported HPHT lab-grown diamond crystal in 1993?
34.80 cts. ## Footnote It took 600 hours, or 25 days, to reach that size.
30
What did De Beers indicate about growing crystals larger than 30 carats in 2000?
They could be grown in less time, but only some areas were gem-quality ## Footnote This indicated improvements in the technology used.
31
What was the annual production of lab-grown diamonds prior to the 2000s?
About 1,000 carats per year ## Footnote This was significantly lower compared to the quantity of natural diamonds.
32
By what year was the jewelry industry beginning to accept lab-grown diamonds as a commercial product?
2003 ## Footnote HPHT diamonds of 2.5 to 3.5 cts. were being produced in commercial quantities.
33
What method was used to produce gem-quality lab-grown diamonds in 2003?
CVD method ## Footnote These diamonds were predominantly brown and often small.
34
What improvements were seen in the quality of CVD diamonds by 2007?
Significantly improved quality and a variety of colors ## Footnote Colors included colorless to near-colorless, orange to pink, and brown.
35
When did Russian firms produce the first HPHT lab-grown diamonds for commercial use?
1990 ## Footnote This marked the beginning of commercial production of lab-grown diamonds.
36
Which companies were involved in growing experimental near-colorless HPHT diamonds in 1990?
* GE * De Beers * Sumitomo ## Footnote These companies were pioneers in the development of HPHT diamond technology.
37
What was the weight of the largest reported HPHT lab-grown diamond crystal in 1993?
34.80 cts. ## Footnote This diamond took 600 hours (25 days) to reach that size.
38
What significant announcement did Gemesis make in 2010?
Plans to market colorless and near-colorless CVD diamonds ## Footnote This was part of Gemesis's strategy to expand their product offerings.
39
What type of diamonds did Chatham offer in 2004?
HPHT diamonds in a variety of colors ## Footnote Chatham was one of the early companies to offer colored lab-grown diamonds.
40
In what year did Gemesis begin producing commercial quantities of HPHT diamonds for jewelry?
2003 ## Footnote This marked a significant step in the commercialization of lab-grown diamonds.
41
Which company produced CVD diamonds?
Apollo Diamond ## Footnote Apollo Diamond was known for its work in CVD diamond technology.
42
What did WD Lab Grown Diamonds do in 2008?
Licensed CVD technology from Carnegie Institute ## Footnote This partnership helped WD Lab Grown Diamonds enhance its production capabilities.
43
What was the turning point in the lab-grown diamond industry?
The announcement by Gemesis Corp. (now Pure Grown Diamonds) to market colorless and near-colorless CVD lab-grown diamonds in 2010 ## Footnote This shift allowed for the production of higher quality diamonds.
44
What technological advancements contributed to the production of near-colorless to colorless lab-grown diamonds?
Advancements in both HPHT and CVD methods ## Footnote These methods enabled the production of larger and better-quality diamonds.
45
Which company began producing large colorless faceted HPHT diamonds in 2014?
New Diamond Technology (NDT) ## Footnote NDT was pivotal in advancing the production of lab-grown diamonds.
46
What was significant about NDT's 2015 diamond production?
NDT produced a colorless, VS clarity, 10.02-ct. faceted HPHT diamond, with a rough weight of 32.26 cts. ## Footnote This was the first colorless lab-grown diamond above 10 carats in faceted weight.
47
What record did NDT announce in November 2018?
The creation of a 55.94-ct. HPHT diamond, which weighed 20.22 cts. once faceted ## Footnote This diamond had orange color and VS clarity.
48
What was the largest HPHT lab-grown diamond announced by NDT in December 2018?
An astonishing 103.5-ct. rough crystal grown in 14 days ## Footnote Although it appeared brownish orange and had poor clarity, it demonstrated significant advancements in production.
49
What factors limit the size of lab-grown diamonds?
Equipment capacity, growth time, and equipment maintenance costs ## Footnote These factors are critical considerations for lab-grown diamond producers.
50
What impact have improvements in lab-grown diamond production had on melee diamonds?
Allowed for mass production of melee diamonds ## Footnote This means that diamonds of nearly any size on the market could be lab-grown today.
51
Fill in the blank: The first company to produce a colorless to near-colorless lab-grown diamond above 10 carats in faceted weight was _______.
New Diamond Technology (NDT)
52
True or False: The majority of lab-grown diamonds were colorless before 2010.
False ## Footnote Most lab-grown diamonds were colored until Gemesis Corp. announced plans for colorless diamonds.

Gemmology (43 decks)

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