What is the Asha made of?
The Asha® diamond simulant (or "fake diamond") is a US Patent pending product that is a composite gemstone consisting of three separate substances combined as follows:
1)High-grade, extremely well cut CZ (Cubic Zirconium)
2) An optical index layer with a refractive index higher than natural diamond
3) An infusion layer of amorphous diamond that completely encases and seals the entire stone. 1)High-grade, extremely well cut CZ (Cubic Zirconia) Benefits: High end CZ has stood the test of time (since 1976) as being an excellent diamond look-alike, or diamond simulant material. It offers a similar refractive index (2.18 vs Diamonds 2.42). Combined with its cubic crystal structure (same as diamond, compared to Moissanite's hexagonal structure) it is an excellent starting substrate material. Drawbacks: 3) CZ is composed of larger molecules than Diamond (Zirconium vs. Carbon). Thus, it slows light down more which means some non-visible light is slowed enough to become visible as 'blue' light. This is the explanation behind why many CZ's have a characteristic 'blue haze' when under certain lights, which is a give-away that it is a fake. 2) An Optical Layer with a higher refractive index than Natural Diamond (2.50 vs. 2.42) Benefits: The optical layer helps boost CZ's lower refractive index to bring it more in-line with diamond visually. Further, the optical layer increases the 'liquid mercury' look that natural diamond has, something that plain CZ normally lacks. 3) An infusion of lab amorphous diamond to completely seal the entire stone. Benefits: Stops the porosity of CZ: The amorphous diamond, being composed of 80% diamond bonds, creates a highly non-porous surface, similar in fact to natural diamond. This prevents oils and other clouding substances from being absorbed the way regular CZ does, and helps keep it cleaner, longer. Stays cleaner, longer: When the Asha was first being made in 2001, we only coated the upper portion of the stone on the initial prototypes. However, testers who had no knowledge that we had only coated the top, immediately began noting that the bottom of their stone rapidly dirtied compared to the top, and so we thus changed to completely coating the entire stone once production began. Prevents the clouding reaction of CZ: As noted, CZ is oxygen deficient, and as such, it constantly tries to 'steal' oxygen by reacting with both water and carbon dioxide. This is the reaction that can lead to a CZ clouding over time, and has in fact been noted on competitors plain CZ product right out of the package.
A discussion of each component involved is presented below:
1) CZ is very porous meaning it rapidly goes opaque (due to absorbing body oils, etc) when worn, and remains flat and plasticy in appearance until cleaned again. Diamond, by contrast, is very non-porous due to carbons extremely small atom size and tight-packing. Diamond mines previously used the non-porosity as a way to sort diamonds out by running a grease belt as only the diamonds would stick due to not absorbing the grease. Thus, the quickness to go opaque when worn is a visual give-away that it is a fake rather than diamond.
2) CZ is inherently oxygen deficient, and thus readily interacts with both carbon dioxide and water which appears to cause the notorious 'clouding' reaction over time.
From Anderson Materials Lab report which showed that the Diamond Nexus Labs "lab diamond" is a plain CZ:
"ZrO2 (CZ)
is susceptible to absorbing water and CO2 to make 3ZrO2 * CO2 *H2O. This reaction may be the cause of the cloudiness that often times besets cubic zirconia in time. With the surface sensitivity of XPS, we may be able to observe the reaction that causes this cloudiness much earlier than it can be seen by other techniques. The amorphous diamond or diamond-like carbon coating of the Asha diamond simulant would prevent this reaction of cubic zirconia from taking place and is another advantage of its use."
The amorphous diamond completely seals the CZ and thus prevents this clouding reaction from occurring.
Improved glossiness and luster: The amorphous diamond, being composed of carbon and thus a smooth, tightly knit surface, helps improve the finished luster and gloss of the finished Asha. It is very similar to the way most auto manufacturers apply a clear coat on top of the paint to improve glossiness.
Improved durability: Due to the amorphous diamonds hardness of roughly 9.7, as well as its having a coefficient of friction that is better than Teflon, it boosts the finished Ashas durability as compared to uncoated CZ.
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The Asha is produced in a clean-room environment, and each Asha undergoes 6 individual inspections during its creation.
The finished Asha has consistently been regarded as the most realistic diamond simulant available and we believe this is directly due to the benefits each of the individual components contributes to the beauty of the finished Asha product.
Sample testing:
Of interest, below is one of the independent tests run to show the amorphous diamond coating layers improvements to the CZ core:
Test 2: Contact angle goniometry
Purpose: To 'visually' show the amorphous diamond coating
Results: The Asha (version 5) with coating showed roughly 300% difference in contact angle as compared to an uncoated Asha core.
[Note: we have long known that the amorphous diamond coating helps keeps the Asha much cleaner, much longer than uncoated Asha or plain CZ as it has a coefficient of friction lower than teflon - this test helps show that effect.]
Uncoated Asha, polished CZ core - contact angle of 98.5 degrees:
Asha with amorphous diamond coating - contact angle of 31.7 degrees:
Test performed by: Future Digital Scientific Laboratories (March, 2007)
[Of interest, contact angle testing has been used to id authentic historical coins vs. otherwise undetectable fakes...because water contains billions of hydrogen atoms, it is very interactive and thus differing material surfaces will show varying contact angles even when other tests do not detect a difference.]
