5 replies to this topic

[sam008]

hey guys

can most people in the industry see a diamond with the naked eye and be able to approximately tell the different grades and thus price in a matter of a few seconds? Just curious

thanks

[denverappraiser]

sam008, on 23 May 2011 - 04:15 AM, said:

hey guys

can most people in the industry see a diamond with the naked eye and be able to approximately tell the different grades and thus price in a matter of a few seconds? Just curious

thanks

No. Actually, there are none who can. MOST can't even tell the difference between a diamond and a CZ without tools.

[davidelevi]

Not "most" but a fair few can have a good guess (most assistants in shops could not tell a diamond from a CZ). It also depends on what the diamond is graded as. Telling SI from VS is relatively easy. VS from VVS or IF much less so, particularly on a set stone. Same for telling J from H, and F from D.

So, if you have a colourless looking stone and you cannot view any inclusions, the safe bet is F/VS1...

Edited by davidelevi, 23 May 2011 - 04:51 AM.

[denverappraiser]

Davide,

I emphatically disagree. Without tools, IF-SI1 will look the same to the naked eye in terms of clarity and many SI2's as well. That's 6 (or 7) of the 10 clarity grades all looking the same. This affects the prices by a a factor of 2. If it's mounted and dirty, Separating SI2 and I1 is impossiblen and often I2's are even hard to rule out. Is that an I2 or a VS with crud on the back? We're talking about clarity grading on a scale with 2-3 grades and even those overlap.

Color has a similar problem. D and I are remarkably similar when viewed mounted with unknown lighting, especially if it's dirty. That's another factor of 2 or more.

Size. The difference i nprice between a 1.95 and a 2.10 is considerable. Often 40% or more. That's not unique. There are a fair number of such boundaries and these are hard to estimate WITH tools, much less with a casual look without them.

Cut. Maybe, especially if it's decently clean. That the one that's most connected to how a stone 'looks' and, other than concerns about damage, a 5 second inspection really will tell you quite a bit. Unfortunately, rather few in the jewelry industry are prepared to actually do that.

Given the above, we're not even within a factor of 5 of landing on a reasonable price by an unaided examination 'within a few seconds', and that's not even considering the issues of treatments, documentation, and branding. NO seller with sense would rely on such an approach for anything but the smallest stones and no buyer with sense SHOULD. It's a safe bet that eye clean and colorless means F/VS? No, it's not, and I can't imagine anyone taking that bet (By the way, I CAN easily imagine someone OFFERING it, but they know more than they're letting on). Sure, if it's priced like an I2/L and you're hoping for a VVS2/F then the amount of the bet is low but that never seems to be the case. Even amateur sellers are smarter than that so the risk is nearly 100% on the buyer.

[davidelevi]

Neil - I emphatically agree with your disagreement. I missed the vital ingredient "naked eye". That way, it's a crap shot.

With a loupe, I think reasonably correct calls on colour and clarity (within a range) can be made on a clean stone - or at least on the amount of dirt. Size is more problematic, but again within a range. Which may well straddle critical numbers like x.00 carats.

[denverappraiser]

On that we agree (we usually do). With a loupe an a tweezer, an expert can tell quite a bit, especially if they're in control of the lighting and the stone is squeeky clean. I would not so far as to say that most workers in jewelery stores have the talent to do even this. Decidedly few do, and a lot of THOSE won't admit it.