FAQ

What are the prices and times of shipping?
Can I pay with Paypal?
Can the stones be heated for use with precious metal clay?
Does Cubic Zirconia fade over time?
How much like a diamond is cubic zirconia?
How do you know fake or real diamond
How is it made?

What are the prices and times of shipping?

The shipping options are: UK 1st Class, orders less than £10: £1.22
UK 1st Class Recorded Delivery: £2.30
UK Special Next day Delivery: £6.58
Europe Airmail, orders less than £15: £2.43
Europe International Signed for£7.32
Worldwide Airmail, orders less than £15:£2.90
Worldwide International Signed for:£8.50

For uk next day delivery, choose special delivery as the postage option. This is only available Monday to Friday. Special delivery dispatch on Friday is not guaranteed for delivery until Monday (exluding bank holidays), but is likely to get there for Saturday.

Orders are sent same day if ordered according to the times below:



Royal mail 1st class recorded delivery is not guaranteed for next day delivery, for next day delivery in the UK choose special delivery


Can I pay with Paypal?

Yes, you can pay with paypal. To pay with paypal just check out normally and select credit card or debit card. Then when you get to the payment page you will be able to pay with your paypal balance.

Can the stones be heated for use with precious metal clay?

Cubic Zirconia can withstand very high temperatures, but sometimes the colours used cannot. The clear cubic zirconia can easily be fired in a kiln and not discolour. The pink, padparadscha and citrine will probably be ok in the kiln and not change colour, but these have only been tested for use with a blowtorch not a kiln. Blue, and green colours cannot be heated, they will discolour. When the jewellery with the stones in it has been fired, do not cool it rapidly, let it cool slowly or the stones will shatter.

I did some testing personally with a blowtorch and a selection of cubic zirconia. I put each gem under the blow torch for 2-3 minutes, here are the results:

White 4mm Round - stable
White 6mm Round - stable
White 6mm Cushion heated for 5 minutes - stable
White 10mm Princess - Shattered
White 16x12mm Oval - Shattered
Hot Pink created Ruby 6mm Cushion - stable & no change in colour
Padparadscha 6mm Round - stable & no change in colour
Citrine 6mm Cushion - stable & no change in colour

I think the bigger gems shattered because the heat at one part was much higher than the heat at the other part so they became unstable. Never cool the stones rapidly after heating else they will shatter, always leave them to cool naturally.

Does Cubic Zirconia fade over time?

Our CZ does not fade over time. Only low quality cubic zirconia, which we do not sell, fades over time. This is because it has lots of microscopic airbubbles that implode in the sunlight and turn the stone a milky colour. I have had some of our CZ's in my window for over 7 years now and they still, once cleaned, cannot be told apart from freshly made stones.

Good quality CZ is very hard, it is 8.5 mohs and cannot be scratched by normal household objects, there are very few things in the world that can scratch a CZ. Because of this a CZ retains its shape and cut for years.

It would be possible for us to use lower quality cubic zirconia and sell our stones for much cheaper, using low quality material but cutting the stones the same way. But after time the stones would fade and the stones might not be used straight away, so might fade before they even go into a peice of jewellery. The prices on our website are cheap, but CZ can be bought even cheaper at lower quality, it can be bought more expensive too and at lower quality. It is important, if buying a big stone to make sure the quality is good and that the stone will not fade over time. A poor quality stone can look nice at first, but will not last.

It is not just about fading over time though, poor quality stones are often cut poorly too and don't look anything like a diamond. These poor quality stones give cubic zirconia a bad reputation, a real diamond would never be cut like that.

How much like a diamond is cubic zirconia?

AAAAA Cubic zirconia is the best diamond simulant in the world. It is very hard or may be impossible to tell apart from a natural flawless diamond by site alone. Some sources say that jewellers can tell by white flashes in the diamond compared to more colourful flashes in the CZ, but other sources say that in controlled experiments experts were not able to pick out a diamond from a number of cubic zirconia. Another source claims an expert could not tell the difference between a CZ replica of a famous flawless diamond and the real thing

The problem is there are different qualities of CZ and the poor quality CZ's can be very poor, looking nothing like a diamond, this gives CZ a bad reputation. Other CZ stones are better quality but poorly cut or polished. It is not fair to judge Diamond CZ by one of these inferior stones. In a controlled test to see if an expert could pick out a diamond from a number of CZ's then the cz stones used would be top quality and cut the same as the diamond. The stones I sell are the best quality and the best cut, when buying a CZ as a diamond simulant you should choose these stones.

I think that identifying a CZ would normally be done by guess work, a CZ is nearly always D white and flawless. A D White flawless stone is rare and very expensive, so unlikely to be a natural diamond, especially if set in a cheap ring. So as soon as one is seen, it would be suspected to be CZ. But, if the stone had flaws and sparkles like a diamond, then it is most likely to be a diamond. We now sell colour G-I CZ, so you can no longer suspect only colour D diamonds

All our Cubic Zirconia is cut and polished to the kind of standard you would expect a diamond to be cut and polished. Diamonds are cut by hand (with a machine) and so are most of our cz's, this makes them look more natural, but also means if you buy 2 they may not match exactly. Our round cz's that are under 5mm are purely machine cut and our hearts and arrows cut stones are cut by a different machine which cuts them to perfection.

How do you know fake or real diamond

There are many ways to tell a diamond simulant from a real flawless diamond. CZ is the only diamond simulant that cannot be told apart by site, other diamond simulants all look different to diamonds. The next best diamond simulant, Moisanite can be told apart from a diamond because it has a yellow tinge and too much fire, whereas White sapphire, does not have enough fire. Diamonds with flaws in them are very likely to be natural, but further tests would be needed to confirm it.

Here are ways to spot CZ or other diamond simulants. Below are the properties of a real diamond compaired to its fakes.

Diamond - Brilliance - 2.42, Fire - 0.44, Hardness - 10, Weight 3.52, Luster 17.2%

A real diamond will nearly always have some kind of flaw that can be seen either by the naked eye, or through a jewellers joupe, or by microscope. A flawless diamond is rare, a 1 carat D colour flawless Diamond costs around £10,000.

Lab Created Diamond - Brilliance - 2.42, Fire - 0.44, Hardness - 10, Weight 3.52, Luster 17.2%

A lab created diamond is not a simulant, it is a created or synthetic gem. This would be the best fake diamond because it would need to be sent to an expensive gem testing lab to discover it was fake, if it was not for the laser inscription that man made diamonds are tagged with. Cubic zirconias and Moissanites are often sold as lab created diamonds, but they are not true lab created diamonds, they are simulated diamonds. The term created diamond or lab diamond is now commonly used to describe cubic zirconia, even cheap, low quality cubic zirconia. Now a lot of people believe that diamonds can be cheaply made in a lab, but it isn't so

At present, January 2009, lab created diamonds are not only produced by a number of labs that have the high technology to produce them. They are expensive and time consuming to produce and because of this the price they sell for is high. Also lab created diamonds are mostly made in the colour yellow and orange because they are easier and cheaper to produce in these colours. The labs that make them inscribe the diamonds with laser to distinguish them from real diamonds.

The biggest clear lab created diamond possible is one of 0.60 carats in size. Coloured diamonds can be made that are bigger than this and in the future, no doubt, it will be possible to make bigger stones. A 0.30 carat clear man made diamond will cost arround £600 the natural equivalent costs about the same. Because of this you don't need to worry about being sold a created diamond instead of a real one. Here are some links to their websites

http://www.gemesis.com/index.cfm
http://www.apollodiamond.com
http://www.lifegem.com/

Cubic Zirconia - Brilliance - 2.15-2.18, Fire - 0.058 -0.066, Hardness - 8-8.5, Weight 5.8, Luster 0%

A thermal diamond tester is the best way to detect a CZ, these can be bought in the UK from around £50, more expensive ones can detect moissanite too.

Hardness test, a sapphire (corrundum) can scratch the surface of CZ, but cannot scratch diamond. A synthetic sapphire can be bought for about £1 a gem, you can buy a lab created ruby from this website, rubies can also scratch cz, if it scratches the surface of the suspect diamond then it is not a diamond. A sapphire cannot scratch moissanite or white sapphire, so this test wouldn't rule out Moisanite or White sapphire.

Weight, a cz weighs a lot more than a diamond, so if it is loose you can weigh it on gem scales to see if it's weight matches it's size. A 1 ct diamond is 6.5mm in diameter and 4mm deep, a CZ of the same size weighs 1.66 cts.

diamond-like carbon Coated Cubic Zirconia

This is a cubic zirconia gem with a layer of diamond like carbon, a coating that has some of the properties of a diamond, how much depends on how it is made and it's quality. The coating makes the cz match the physical properties of a diamond more, but this does not make the cz look more like a diamond to the naked eye, as it is already impossible to tell the difference by sight alone. The diamond-like carbon Coated CZ's cannot fool a thermal diamond tester.

Moissanite - Brilliance - 2.65, Fire - 0.104, Hardness - 9.25, Weight 3.21, Luster 20.4%

Despite it's impressive physical properties match, it sparkles too much to be a diamond because the fire is more than twice the amount of a diamond and has a slight yellow glow. Moissanite will pass a thermal diamond tester because it is similar to a diamond in chemical structure, but you can now buy thermal diamond testers that also test for moisanite, you can buy one in the uk for about £150.

Cubic zirconia is used to fake moissanite too, a fake fake. Moissanite is quite expensive, it costs over £200 a carat. It is not actually classed as a diamond simulant, but is sold as an alternative to diamond. People buy moisanite for it's own unique characteristics especially it's fire. You can buy loose moissanite stones from here

White Sapphire - Brilliance - 1.77, Fire - 0.18, Hardness - 9, Weight 4, Luster 9%

A white sapphire will just look too dull to be a diamond because of it's low brilliance and fire. But still to the untrained eye it would be hard to confirm that you have not been sold a fake. A thermal diamond tester will easily distinguish between a diamond and a white sapphire.

Conclusion For peace of mind, if you are somebody that buys diamonds it would be a good idea to purchase a good thermal diamond and moissanite detector. The diamond tester setting will tell you if the gem is a diamond or moissanite, then you can use the moissanite detector setting to test if it is moissanite.

How is it made?

CZ nearly always refers to synthetic man made cubic zirconia, but it also occurs naturally, natural cz is very rare. Synthetic CZ is made by heating zirconium oxide powder up to nearly 5000'F. Because it is so hot the powder needs to be heated from the centre outwards by radio waves so that the outer powder which is cooled by copper water pipes forms a crucible to contain it. As the mixture cools cz crystals grow. The zirconium oxide powder needs stabilisers and needs to be cooled carefully, the right balance of stabiliser and careful cooling determine the quality of the cubic zirconia.

The best quality crystals are flawless and are 8.5mohs in hardness. Lesser quality cubic zirconia is not so hard and may have small bubbles that implode and cause the stone to discolour over time, this doesn't happen with high quality cz. Because of its hardness it will last a long time, below is the mohs hardness scale, anything on the list can cut something with a lower number, but that item with the lower number cannot even scratch the surface of something with a higher number. You can rub cz with sandpaper (not wet and dry) and it doesn't scratch.

1 Talc
2 Gypsum
2.5 to 3 pure Gold
3 Copper
4 Flurite
4.5 Platinum
5 Iron
6 Titanium
7 Glass
7 to 8 Hardened Steel
7 to 8 Sandpaper
8.5 Cubic Zirconia
9. Emery Cloth, Corundum, (sapphire, rubies, scratch proof glass on watches)
10. Diamond, diamond coated tools.


Contact information:

Email: sales@diamondcz.co.uk

Please ask questions using the link above to sales@diamondcz.co.uk