Tag: diamond study

NCDIA – JCK Recap – How to Maximize your business with Natural Color Diamonds!

May 29, 2015 – Las Vegas  JCK –
 SeminarPanel - JCKHeadShots
NCDIA was invited back to host a special panel seminar in part of the all new JCK Talks segment during JCK Las Vegas. NCDIA is a non-profit, membership-based organization with multi-national members including mining companies, diamond and jewelry manufacturers, designers and retailers. The NCDIA’s mission to train, enlighten and educate the global community about natural color diamonds.
This expert panel included:
  • Thomas Gelb – NCDIA
  • Jordan Fine – JFine, Inc.
  • Sean Moore – Borsheims
  • Pratima Sethi – Sethi Couture
  • Jim Pounds – Dominion Diamonds
  • Rob Bates – JCK (Moderator)

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Below you will find a few excerpts from our panel seminar, the full video will be available in August via JCK.com

Rob Bates – As a retailer, How do you source them? 

Sean Moore: As a retailer it is important to develop relationships with vendors who carry Natural Color Diamonds, some buyers don’t understand the importance in sourcing color. It took me about 5-6 years to learn who the players were, who owns what products and which of them were treating me fair.

Rob Bates – As a designer, what have you learn from the customers?

Pratima Sethi: What i find fascinating is the educational factor for consumers and how long it has taken them to understand color. 5-6 years ago customers were just intrigued and weren’t aware of the vast color shades available. Today consumers are becoming more sophisticated, it’s all about design and personalization when it comes to purchasing these diamonds.

Rob Bates – Are customers asking about certain colors?

Jordan Fine: There is a growing interest in natural color diamonds at the consumer level. For example it comes down to what is in the retail store, in the last 10 – 15 years consumers have seen yellow and browns at NCDIA’s retail stores. Consumers are on to color and retailers are starting to pick up on this by introducing new colors such as Pinks, Blues, Orange etc.

Rob Bates – Is there certain customers that look for color, who is buying them?

Pratima Sethi: It’s not necessarily a rich person, and that is what makes color diamonds great is that there is this range of price from affordable to valuable. And as a designer who works with Natural Color Diamonds, we need to break that notion that this product is not just for the wealthy but for everyone. They are beautiful, unique and obtainable to buy.  You can attract a person early on with champagnes and build that business over time to go into yellow, pinks etc.

Sean Moore: The majority of the colors that we carry are brown, yellow and black, and customers who don’t want to spend the money on white diamonds can pick up a champagne diamond that can be more beautiful and affordable.

Rob Bates – How do you price the more rarer color diamonds?

Tom Gelb: There is no methodology to determine what color is, the grading system is quite complex. We can at least guide them to what direction.

Jordan Fine: Obviously for a color stone, i would pay more for a stone that is Vivid rather than a stone that is Fancy. Certain flavors have the WOW factor and it’s all about taste.

Pratima Sethi: There is ways of of taking advantage of the demand in color. Color diamonds are similar to art, with the large color palette.

Sean Moore:  Some retailers look towards the auctions houses as a starting point for pricing and while that information is very valuable, i do encourage you to find the right vendors to work so you can find the best price. Your ability to get the goods is a big factor in pricing. There is an increased growth in interest from the consumer level . When customers hear a price of a blue, it’s very hard to market something that is not affordable to general public.

Rob Bates: Has the investment market in particular changed?

Jordan Fine: NCDIA does not endorsed investments as none of us can tell the price and future growth. However some stones have appreciated in value. In terms of investment, there is some issues to tackle.

Sean Moore:  For us, investments are not for us.. We don’t endorse Natural Color Diamonds as an investment however we do show customers the growth when customers do ask us about this.

Rob Bates:  There use to be a stigma against browns, do you still see this? And what about Yellow?

Jim Pounds: Fancy browns exudes warmth and they are very much in demand and yellows in there full range have developed to the retail level, they are just stunning. I don’t see any stigma against yellows.

Rob Bates: Lets talk about supply? Who will fill the gap with Pink once the supply of Argyle is complete. 

Jim Pounds: From the Dominion Diamond Group, we don’t see any significant growth in production of Pink Diamonds, a few more yellows but it is a challenge to maintain supply. Argyle from what we know could extend to 2020 and beyond however with the economics it’s really the direction that Rio Tinto wants to take

Rob Bates: Lets talk about synthetics and new treatments. 

Tom Gelb: The push from what i have seen has always been with white goods. With treatments it use to be people in their garages, however it’s a bit more complex now as “scientists” have been getting involved. But the ultimate goal for these guys are white goods.

 

 

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Physicists spy on random motion of electrons with defective diamonds

By Chris Lee

Spurned electrons throw light on electronic noise at very small length scales.

Normally, noise is something we scientists try to avoid. In the most advanced physics experiments, the goal is usually to measure something new. If you ever ask the experimenters why it took them so long to do a measurement, the most common answer is “finding a way to defeat the noise.”

Sometimes, though, the noise becomes more interesting than the signal, telling us new things about the physical system we are studying. The study of noise is not new, of course, but with our increasingly precise control of quantum systems, we can study it in ever finer detail.

In this case, researchers studied Johnson noise, otherwise known as white noise. In a metal, there is a sea of electrons that is free to travel around in constant motion—the fact that the temperature is above absolute zero is enough to keep electrons in motion. Because of this motion, the density of electrons varies slightly from place to place at any given time. These fluctuations create small attractive and repulsive forces that drive electrons to attempt to neutralize the fields. In doing so, they create new density fluctuations and fields in an endlessly repeating cycle.

If you could freeze the electrons and examine the density as a function of position along a wire, you would find that the density fluctuations occur at huge range of length scales. That is, there are density waves with lengths that are very long—the length of the wire, in fact—and there are density fluctuations with shorter wavelengths. The result is tiny electrical currents that have frequency components that occur at all time scales. You cannot escape this white noise—it’s everywhere.

All of this hides the motion of individual electrons, though. An electron sitting in this sea will feel a force and start to move in a particular direction. However, the metallic crystal isn’t perfect, so it hits an imperfection in the crystal—an imperfection might be a missing atom, or it could be the boundary of the crystal or a range of other deviations from the regularity of the crystal structure. When an electron hits an imperfection, it stops dead (contributing to those density fluctuations we discussed early) before starting to drift off again in whatever direction the local electric fields tell it to go.

This behavior means that when you look at a current flowing through a wire, it looks more like water diffusing through sand than water flowing through a pipe.

Using diamonds to see current

How could you possibly observe this behavior in detail? Using impure diamonds, as it turns out. I’ve discussed nitrogen vacancies in diamond in the past. Essentially, a carbon atom likes to be surrounded by four other carbon atoms. Nitrogen, on the other hand, only likes to have three atoms around it. If nitrogen is substituted for one of the carbon atoms, it cruelly rejects one of its neighbors. The electron proffered by the carbon atom is left stranded between a cold and uninviting nitrogen atom and a carbon atom that would sooner be rid of it. The nature of these surroundings gives the electron a very well-defined energy level structure, creating what is called an NV- center.

What makes the NV- center special is that the excited state has quite a high energy, so you need to use green light to drive the electron into it. Even better, both the excited state and the ground state have a couple of additional energy levels associated with the spin orientation of the electron. The energy difference among these levels is very low. The probability of the ground state electron being in any one of them depends very much on the surrounding magnetic field, which makes it very sensitive to stray electrical currents (which generate a magnetic field).

This provides a convenient way to measure tiny electrical currents: first use an optical light source to drive the NV- center into a specific state. After a short time, probe the NV- center to see if it is still in that state. In that intervening time, the stray current will sometimes cause the NV- center to change state, telling you something about the local environment at that time. After many repeated measurements, you end up with a picture of the currents flowing in the vicinity of the NV- center.

The vast majority of all diamonds contain some nitrogen. In most yellow diamonds the nitrogen atoms have grouped themselves in very specific ways. This happens during and right after the diamond is formed. These nitrogen arrangements absorb light in the blue region of the spectrum producing a yellow color. Yellow diamonds can contain an orange, green or brown modifying color states NCDIA

Watching the current flow

To put this into practice, the researchers created a diamond that had individual NV- centers lying just under the diamond’s surface (5-25nm below the surface). They next coated the top of the diamond with silver to provide a local source of stray currents. They were then able to measure the noise currents (or, more specifically, the magnetic field associated with the noise current) for a range of temperatures. These measurements, though, cannot be understood all by themselves, because they are very local, while the current is also determined by the bulk properties of the silver.

When these measurements were coupled to measurements of the bulk conductivity of the film, it was possible to determine that, as expected, the electrons behaved like they were diffusing through the metal. That is, the electrons were bouncing around in the metal, and a lot of that bouncing was happening at the boundaries between silver crystals.

In a second experiment, the researchers used a silver film that consisted of just a single crystal. For bulk measurements, the diffusion model still fits the observations—the silver atoms are vibrating, creating places for electrons to scatter. But on the scale of the NV- center, the diffusion model fails (at least at low temperature). Instead, a large fraction of the electrons pass over the NV- center without scattering at all.

These sorts of measurements are very useful. Since the NV- center is not in contact with the conductor, it provides a cleaner measurement technique, avoiding problems associated with making electrical connections at very small scales. Understanding noise and current flow at smaller and smaller length scales may also have technological relevance for designing and fabricating semiconductor circuits.

Information Courtesy of – ArsTechnica.com

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