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Diamond CZ


When are gems restocked?
What are the prices and times of shipping?
How long will my order take to arrive?
What stones are the best quality?
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 CZ made?

Do your gems come with certificates?

When are gems restocked?

Most of diamondcz gems are hand cut and polished to perfection. They are cut in China in a big batch, when the batch is finished it is sent to the uk and the website is restocked. We are constantly cutting gems to restock the website and are working as fast as possible to restock every gem that is out of stock. But it is impossible to say when a certain gem will be back in stock because there is no set completion time for a batch of gems.

What are the prices and times of shipping?

The shipping prices are shown when you add an item to your shopping basket. There are postage discounts for some methods of posting based on how much you spend on gems. If you order over £20 the method of posting will change to a signed for delivery and the shipping price will be increased to cover the cost of signed for mail.

For uk next day delivery, check the dispatch time (below) first to make sure that the order will be dispatched today and then choose special delivery as the postage option. 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 the same day if ordered and paid for according to the times (24 hour GMT) below:


Monday 11 July: Order before 9:00
Tuesday 05 July: Order before 9:00
Wednesday 06 July: Order before 9:00
Thursday 07 July: Order before 9:00
Friday 08 July: Order before 9:00

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

How long will my order take to arrive?

In the UK, orders sent by first class or first class recorded delivery usually arrive the next day when paid for according to the times shown above. But only special delivery is guaranteed for next working day delivery. Orders sent by first class or first class recorded are not considered lost until 14 working days have passed.

Outside of the UK
Orders sent to destinations outside of the uk by normal airmail can take anywhere from 5 days to 40 days to be delivered. There are also delays caused by customs in the destination country. Shipping times to the US take on average 10-15 days to be delivered, but often there are times where there are delays and the orders can take around 3 weeks or longer to arrive. Choosing International signed for speeds up the delivery time

How are CZ gems Graded?

There is no official grade for cubic zirconia, but manufacturers grade their own gems, this means that AAA gems from one manufacturer could be better than AAAAAAA from another. Some cuts are cut purely by machine, others with machine assistance and others need to be hand cut with just a lap, whatever is best for the look of the finished gem:

The material and the cut are graded differently. The cost of labour is higher than the cost of material, so it would not make sense to use anything lower than AAA material good quality cut gems.

A - Flaws cracks and air bubbles
AA - A few flaws cracks and air bubbles
AAA - No flaws and cracks or air bubbles

Some material has more clarity than other material, this is only evident when the gem is cut and some gems look better when the material is less clear. The material is not graded for clarity, only the cut gems are graded. The material is bought at a market where experts choose the best material they can get for the gems that need to be cut. The best most expensive material is not always the best choice for every type of cut.

Cut Gems, graded by light return, sparkle, luster and clarity
AB - Worse(not the same as Aurora Borealis coating which is abreviated to AB)
A - Bad
AAA - Good and uses AAA material
AAAA - Very Good and uses AAA material
AAAAA - Excellent and uses very clear AAA material
6A, Hearts and Arrows, Star Machine, Swarovski - Best using the best material and cut to exact measurements to display hearts and arrows under hearts and arrows scope. The hearts and arrows I sell on my website are 6A quality and the 6A are all hearts and arrows cut, which means perfectly cut with best quality material and polishing. Swarovski and Star machine cut are brand names of high quality cz, both are highest quality so it is down to the preference of the customer which they perfer.

Ungraded Stones

A lot of the stones on the website are ungraded, this is because everything on the website used to be 5A quality which was the highest grade at the time. Anything ungraded is at least 5A. There was no 6A grade at the time of cutting, if there was, some or all of them would be graded 6A.


If a batch of 3A stones is ordered, then 3A is the minimum standard those stones can be cut to. However the 3A gems could come out looking as good as 6A, although it doesn't happen often. So it is possible to buy a 3A stone and get a 5A or 6A stone, but not possible to buy a 6A stone and get a 3A stone.

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

Cubic Zirconia - Brilliance - 2.15-2.18, Fire - 0.58 -0.66, Hardness - 8-8.5, Weight 5.8, Luster Adamantine

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 biggest problem with this stone is not knowing whether you have bought a normal cz sold as coated, or a real coated one as the only test that can be applied will destroy the stone: If a stone is coated and it claims to be higher than 9 mohs, then it should be able to scratch the surface of a sapphire and a sapphire should not be able to scratch it back, if the sapphire easily scratches it then it is below 9 mohs and likely to be cz with no coating. 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 moissanite, 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 moissanite 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.

Heat Treated Diamond 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.

The hardness of quartz is important to a gemstones lifetime. Quartz is all around us in dust and scratches the surface of any item which is less than 7 mohs of hardness which includes any gemstones less than 7 mohs which are in your jewellery. Cubic Zirconia is 8.5 mohs so is never affected by quartz.

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

Do your gems come with certificates?

Our gems do not come with certificates as it is best for the customer to certify the gem themselves for peace of mind. The problem with certificates is that they are easily faked. If a gem dealer is dishonest and selling fake gemstones, then they can easily just print off fake certificates, so what use is a certificate if it is sold along with the gemstone. The cheapest prices I have seen for gemstone certification is about �20 - �200 a gem, depending on how hard it is to identify the stone, so if you buy a gem with a certificate and the gem costs the same as gems without the certificate, then it is likely just a printed certificate which is worthless. When I receive gemstones such as moissanite which are expensive, I can identify them myself with various tests, for example, out of many fake diamond types only moissanite can pass an electronic diamond tester test, it also has a doubling effect when viewed under a loupe and it is hard enough to scratch sapphire. The only way to be sure is to learn about how to test the gem and test it yourself, or send it off yourself for testing. Contact information:


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