Huh? They had me at $7000
Win a GIA-Certified 0.50ct Diamond Worth over $7,000 from Q Report
57
Dates
Closing Date
15/12/2018
Prizes
Description
GIA-Certified 0.50ct D VVS1 Diamond.
No. of Prizes
1
Entry Requirements
Open To
Australia-wide
Entry Limit
One per person
Entry Methods
Website
Prerequisites
n/a
Related Stores
closed Comments
I'd say that valuation is dodgy. The stone has a high clarity and perfect colour, but the main factor that effects how sparkly a stone is (or how much light it returns) is the cut. The angles of this cut are't great for light return. Additionally this has high flourescence (ie it will glow under UV light). Stones with high fluorescence can look really dull or hazy under sunlight.
For the same money its better to compromise on clarity and colour and get a better cut diamond with less fluorescence.
According to the GIA:
"IA studies show that for the overwhelming majority of diamonds, the strength of fluorescence has no widely noticeable effect on appearance. In the GIA Fluorescence Study, it was found that the average person could not make a distinction between a diamond with fluorescence and a diamond without."
https://4cs.gia.edu/en-us/blog/understanding-diamond-fluores…
I wonder where this dislike for fluorescence actually came from?
@000lynx: This GIA study is well known and the methodology and conclusions they drew from the data have been picked apart and criticised (like this, for example).
Suffice to say while not all fluorescent diamonds will look milky, and some lower colour stones might even benefit from feint fluorescence, there still is a slight risk that some strongly fluorescent stones will look hazy. I wouldn't say "always avoid diamonds with any fluorescence" as one experienced diamond dealer recently told me, but I'd say if you're buying a strongly fluorescent stone, make sure you see it in person under sunlight.. ideally next to a stone without fluorescence for comparison, before parting with your hard-earned money.
I dunno man, the crown angle's a big steep but the gown is elegant and flowing. While the fluorescence may be very strong the effervescence is mild and helps emphasise it's grandiosity. High clarity is of course the best for an intellectual diamond owner although I'd agree a super villainous cut would be more suitable.
lolwut
What, you don't know all the diamond terms? You seemed so clued in.
I admit I approach the quality based primarily on it's ability to power a moon mounted laser beam, which is kind of niche.
The cut grade is excellent - there is no higher Cut grade on the GIA Scale?
Correct. Its a perfect demonstration of why the GIA cut grading is really not especially great for predicting the light performance of a stone. The Holloway cut advisor (mentioned by u/Krz1-d3k0d3 below) is a great rejection tool (put the proportions in and basically don't bother with anything that gives a score lower than 2). If you want a really stunning stone look for:
Table %: 54-57
Depth %: 61-62.5
Crown Angle: 34-35
Pavilion angle: 40.6-41
Lower Girdles: 75-80
Star Facets: 50-55
Girdle Thickness: Thin-Medium-slightly thickAdditionally you might want to ask for an ASET scope image to double check for light leakage.
You can find a 0.5 carat stone that is within these proportions, for well under $3000 online at a place like bluenile. It might have a lower colour rating (say E or F, which most people wont be able to distinguish from a D anyway) and a lower clarity, Say VS2 or SI1, but still eye clean - with no dark inclusions and nothing under the table (so you won't detect anything with the naked eye or even at 10x magnification) - but I guarantee you it will look way brighter and more sparkly than the stone being given away here.
Hca score is 3.7, so it is a pass.
Diamond exchange has a 0.6 carat with similar cut proportions, D colour VVS1 clarity for $3.6k Inc gst. Says a lot if diamond exchange are cheaper than the valuation.
My wife can criticise the declared value all she likes, but if you win it for a $0 outlay (minus your email and marketing value if not using a spam email address), I imagine there'd be no complaints!
Crown angle is a bit steep, depth is a touch too high and fluorescence is very strong.. would have been better if they chose a stone with a lower clarity and colour but with a super ideal cut and feint or zero fluorescence.