MENU LOG IN CART {{currentCart.getItemCount()}}

JEWELRY KNOWLEDGE

What is cubic zirconia (“CZ”)?

CZ is not the abbreviation of man-made diamonds but refers to cubic zirconia (also known as Soviet diamond). Its Mohs hardness is slightly higher than 8 and initially developed by Russia. The synthesized material is hard, optically flawless and usually colorless, but may be made in a variety of different colors. CZ is considered the most convincing and successful diamond simulant to date. Without a 10x magnification loupe, at arm’s length even a jewelry expert cannot be sure to tell the difference between CZ and natural diamonds because of their very similar optical characteristics.

 

Why is cubic zirconia commonly used as diamond simulant?

The nature of CZ and natural diamond is very similar, regardless of the refractive index, dispersion, specific gravity, hardness. The hardness of CZ is between 8.5 and 9.0 (whereas the hardness of diamond is 10), which makes it unlikely to be damaged or scratched. The durability and appearance of CZ and diamond is very similar. Therefore, CZ is still considered as the most important diamond substitute.

 

Dispersion (or "Fire")

The dispersion of CZ is 0.066, which is higher than that of diamond of 0.044. CZ looks more brilliant than diamond.

Hardness

The hardness of diamond is 10 whereas the hardness if CZ is between 8.5 and 9.0, which is harder than most of the natural gemstones, and therefore not easily damaged or scratched.

Specific gravity

CZ is 1.7 times heavier than diamonds. But this feature can only be used to distinguish unmounted gemstones.

Flaw

Basically the CZ produced nowadays is internal and external flawless. Natural diamonds are rarely completely internal and external flawless.

Refractive index

The refractive index of CZ is 2.17, slightly lower than the diamond of 2.42. Due to different refractive index, the cutting of CZ will be slgihtly differnt   from that of the diamond. Such difference can be found by careful observation with a magnifying glass.

Color

Completely colorless diamonds are very rare. Most diamonds are yellowish in color. But CZ can be made to the best color, that is D-level color.

 

 

How to determine the quality of diamond and diamond simulant?

Quality and Value of diamond is determined by four factors. These factors are also termed as 4 Cs or Four Cs where Cs stand for:

 

  • Cutting
  • Color
  • Carat
  • Clarity

 

(I) Cutting

 

The way a rough stone is cut has a great impact on its brilliance and sparkle. It is not enough that a diamond is big, clear and white. No diamond can be truly attractive unless it sparkles, and it won’t sparkle unless it’s properly cut.

 

Cutting style refers to the way in which a stone is cut or faceted. Based on scientific examination, brilliance cut can radiate the largest part of light and is known as the cutting that produces the best sparkle and fire. The term emerald cut has a double meaning. It indicates that the shape is square or rectangular with clipped-off corners and that the faceting style is a step cut, which has parallel rows of long, four-sided facets. A radiant cut has the same shape as an emerald cut but has facets similar to those of a round brilliant cut.

 

(II) Color

 

White diamonds are graded between ‘D’ (colorless) to ‘Z’ (off-white or tinted light yellowish diamond) grade on the GIA International Diamond Grading Scale. On this scale, each grade varies with color.

 

Color

GIA

IGI

UK

China

Colorless

D

Exceptional White Plus

Blue White

100

E

Exceptional White

Finest White

99

Near-Colorless

F

Rare White Plus

98

G

Rare White

Fine White

97

H

White

White

96

Slightly yellowish

I

Slightly Tinted

Commercial White

95

J

Top Silver Cape

94

Light yellowish

K

Tinted White

Silver Cape

93

L

Light Cape

92

M

 

Cape

91

N

90

 

O

Yellowish to Yellow or Browish to Brown

Dark Cape

89

Yellowish

P-V

88-82

 

 

(III) Carat

 

It’s used as a measurement of weight for faceted precious stones. Since 1913, most countries have accepted that 1 metric ct equals 200 mg, or 1/5th of gram.

 

 

(IV) Clarity

 

Clarity of diamond affects the beauty and price of diamond. Clarity refers to how clear the diamond is. It implies the presence or absence of inclusions (internal flaws) and blemishes (external flaws) in diamond. Diamond flaws adversely affect the reflection of light through stone and thus affecting its sparkle.

 

 

GIA Clarity Scale

FL

Flawless - No inclusions or blemishes are visible to a skilled grader using 10×   magnification

IF

Internally Flawless - No inclusions and only blemishes are visible to a   skilled grader using 10× magnification

VVS-1

Very, Very Slightly Included- Inclusions are difficult for a skilled grader to see under 10× magnification

VVS-2

Very, Very Slightly Included- Inclusions are difficult for a skilled grader to see under 10× magnification

VS-1

Very Slightly Included - Inclusions are minor and range from difficult to somewhat easy for a skilled grader to see under 10x magnification

VS-2

Very Slightly Included - Inclusions are minor and range from difficult to somewhat easy for a skilled grader to see under 10x magnification

SI-1

Slightly Included- Inclusions are noticeable to a skilled grader under 10x magnification

SI-2

Slightly Included- Inclusions are noticeable to a skilled grader under 10x magnification

I-1

Included - Inclusions are obvious under 10× magnification and may affect   transparency and brilliance

I-2

Included - Inclusions are obvious under 10× magnification and may affect   transparency and brilliance

I-3

Included - Inclusions are obvious under 10× magnification and may affect   transparency and brilliance

 

Typically we yield a clarity of "FL" (flawless) to "IL" (internally flawless) although VVS1 (very very small inclusions) can be noted in some larger stones.

 

Why is cubic zirconia more preferred than crystal?

CZ is a high quality man-made gemstone and is usually made in a lab. The amount of each ingredient is carefully controlled, resulting in amazing fire and brilliance and certain additives sometimes being used to achieve a similar appearance to genuine diamonds. Because of the process used to make CZ the cost to purchase them is higher than crystals.
 
Hardness for crystals is 6 to 7 on the Mohs scale so its susceptible to scratches and chipping from wear and tear. While the hardness for CZ is 8.5 to 9, it offers a more hard-wearing solution for adding a diamond substitute to your jewelry designs.
 
Crystal sometimes has too many facets and too much fire to pass for a diamond. The dispersion between CZ and diamond is closer than that between crystal and diamond.

 

How to clean gemstones?

The safest way to clean a gemstone is to regularly wipe it with a soft cloth moistened with warm soapy water. Then dry it with a soft, lint-free cloth. Gems that are not damaged by ammonia can be cleaned by spraying them with a window cleaner. If the dirt cannot be washed off with a cloth, try using a toothpick to remove it. If that does not work, have it professionally cleaned.
 
Cubic zirconia is sensitive to high temperature. Avoid exposing your jewelry to sudden changes of temperature which could possibly cause the stones to crack or shatter.
 
If possible, put your jewelry on last, after applying make-up, spraying your hair, wearing perfume and lotions.