Diamond material


23.12 Definition of the word “diamond.” (U.S. FTC, Federal Trade Commission)

(a) A diamond is a mineral consisting essentially of pure carbon crystallized in the isometric system. It is found in many colors. Its hardness is 10; its specific gravity is approximately 3.52; and it has a refractive index of 2.42.

Laboratory-created stones (also called laboratory-grown, or manufacturer-created stones) have the same chemical, physical, and visual properties as natural gemstones, but they are manufactured.

Summary of Basis and Purpose for the Revised Jewelry Guides – August 8, 2018

The final Guides therefore eliminate the word “natural” from the diamond definition. When the Commission first used this definition in 1956,432 there was only one type of diamond product on the market – natural stones mined from the earth. Since then, technological advances have made it possible to create diamonds in a laboratory. These stones have essentially the same optical, physical, and chemical properties as mined diamonds. Thus, they are diamonds. The distinctions between these lab-created diamonds and mined stones are addressed elsewhere in the Guides.433 Because it is no longer correct to define diamonds as “natural,” the final Guides do not include “natural” in the diamond definition.

What is a diamond

A diamond consists of:

Crystallized carbon
(Pure Carbon, cubic C)

Diamond is the cubic modification of carbon and, as a naturally occurring solid, is a mineral from the mineral class of the elements. Diamond usually forms octahedral crystals, often with curved and streaky surfaces. Other shapes observed are the tetrahedron, dodecahedron and the cube. The crystals are transparent, colorless or colored green, yellow, brown and, more rarely, orange, blue, pink, red or gray to black due to impurities (e.g. nitrogen or boron) or crystal lattice defects.

What are diamonds made of? Material laboratory diamonds and mines diamonds. Both consist of the same material: crystallized carbon
What are diamonds made of? Material laboratory diamonds and mines diamonds. Both consist of the same material: crystallized carbon

Carbon (chemical element “C”)
Essential element of the biosphere

Carbon (Latinized carboneum or carbonium) is a natural substance that occurs frequently on earth. Carbon is a chemical element with the element symbol C and the atomic number 6. It occurs in nature both in a dignified (pure) form (diamond, graphite, chaoite) and chemically bound (e.g. in the form of carbides, carbonates, carbon dioxide, petroleum, Natural gas and coal). Carbon is an essential element of the biosphere; in all living beings – after oxygen (water) – it is the most important element in terms of weight. All living tissue is made up of (organic) carbon compounds. Geologically, on the other hand, carbon is not one of the most common elements, because the mass fraction of carbon in the earth’s crust is only 0.027%.

Diamond is the hardest natural substance

In the Mohs hardness scale, it has a hardness of 10

Its grinding hardness according to Rosiwal (also absolute hardness) is 140 times greater than that of corundum. However, the hardness of the diamond is different in different crystal directions (anisotropy). This makes it possible to cut diamond with diamonds. In the diamond powder used for this purpose, the crystals are in every orientation (statistical isotropy), so that the hardest of them always act on the body to be ground.

Diamond is optically isotropic with high light refraction and high dispersion

It sometimes shows fluorescence and phosphorescence and is triboelectric. It has the highest thermal conductivity of all known minerals.

The weight of individual diamonds is traditionally given in carats, a unit that corresponds exactly to 0.2 grams (see section “Weight in carats”). An untreated diamond, ie in particular an uncut diamond, is called a rough diamond.

Hardest substance on earth

practically indestructible

The diamond is the hardest natural substance on earth. On the Mohs hardness scale, it has a hardness of 10. It can cut any kind of rock or metal, but only another diamond can cut a diamond . To burn a diamond, it has to be heated to between 1,290 and 1,650 degrees Celsius. But the oil that is deposited by the mere touch of a human finger can cause dirt to build up and this almost indestructible gemstone quickly loses its sparkling charm.

Diamond Property Mined Diamond Lab Diamond
Chemical Composition C (Crystallized Carbon) C (Crystallized Carbon)
Crystalline Structure Cubic Cubic
Refractive Index 2.42 2.42
Dispersion 0.044 0.044
Hardness 10 10
Density 3.52 3.52
Comparison of properties of mined and lab diamonds

Difference diamond versus gold (periodic table of chemistry)


“C” Carbon

Many people think a diamond is a commodity like gold.
-> That’s not entirely correct.
Diamond = crystallized carbon -> chemical element = “C” Carbon.
Gold = chemical element “AU”.
The material of diamonds is crystallized carbon! That is, the most valuable form of carbon.
“Carbon” (C) is the element of the chemical periods table.
A diamond in this form is not an element of the chemical periods table like gold (AU).

Technological progress

This fact opens the technical possibility for the production of diamonds.
That is, if you technically manage to convert the chemical element carbon (C) into its most valuable form “crystallized carbon”, then you have created a diamond.
For example, carbon in the form of “graphite (= pencil point) “with soft plate-like arranged atomic structure -> in “diamond” with cubic cube-shaped very stable arranged atomic structure.
Conversion of carbon (C) -> into “crystallized carbon (cubic C)” = diamond.

With gold (AU), on the other hand, you would have to be able to split atoms to make it, and so far that has not been possible.

Lab-Grown Diamonds = same material, same atomic lattice structure

Lab grown diamonds are made of the same material (= crystallized carbon) as mine diamonds and have the same atomic lattice structure. This means that the carbon atoms are arranged in the same way in both rennet diamonds and mine diamonds = cubic (cube-shaped)!

What more could you want?
Same material, same atomic lattice structure – optically, chemically and physically identical!

Chemical crystal structure of graphite and diamond in comparison


Type I & Type II

Type II (only 2% of mine diamonds = purest, most expensive and most sought after white diamonds).
Virtually all rennet diamonds are Type II. ….Thus, they are among the best 2% in terms of quality, with virtually no nitrogen impurities.

Diamonds are mainly made of carbon. However, there are other elements that are part of the diamond’s internal structure, and these affect the color grade of fancy color diamonds.

  • Type I
    • Diamonds WITH nitrogen (N) atoms (= “nitrogen group”)
    • approx. 98% of all mined diamonds
    • IaAB, IaA, IaB and Ib (depending on the way nitrogen combines with carbon in the internal structure of the diamond).
    • white diamonds → nitrogen in them is not “light-absorbing
    • e.g. yellow (Yellow), orange (Orange) → nitrogen in them absorbs color
    • brown, in some blue & green & in australian pink diamonds
  • Type II
    • almost 100% nitrogen-free (= WITHOUT nitrogen)
    • approx. 2% of all mine diamonds → very rare group of diamonds
  • Type IIa
    • purest diamonds = consist almost entirely of carbon
    • they can be colorless (White), brown (Brown) or pink (Pink)
  • Type IIb
    • ultra-red and nitrogen-free
    • blue fancy diamonds (Fancy Color BLUE)
    • contain boron (B) atoms → this boron in the otherwise pure carbon atom structure is responsible for the blue color in blue fancy diamonds
    • conduct electricity

Difference diamond versus zirconia and moissanite

Synthetic Cubic Zirconia (CZ)

Zirconia are made of zirconium(IV) oxide. They are very cheap fake diamonds “Diamond Simulants”. Repeated contact with water will damage the stone. This is a completely different material and never has the hardness and longevity of a diamond (8 versus 10). Cubic zircon will last two to three years with daily wear, as long as you clean and care for your jewelry. With occasional wear, a cubic zirconia can last up to five years. Over time, zirconia usually becomes scratched and cloudy. Cubic zirconia becomes cloudy over time due to scratches, soap and mineral residues, dirt, and exposure to oxygen in air and water.

Synthetic Moissanite (SIC)

Moissanites are made of silicon carbide. These are also not diamonds, but an imitation “Diamond Simulants”. This is also a very different material and although very hard, does not have the hardness (9.25 versus 10) and properties of diamonds. Moissanite is closest in physical properties to diamond than any other diamond simulant. But are clearly fake diamonds and can be distinguished by experts.

Property Synthetic Cubic Zirconia Synthetic Moissanite
Chemical Composition Zirconium(IV) oxide Silicon Carbide
Crystalline Structure cubic crystalline form of zirconium dioxide (ZrO2) Hexagonal
Refractive Index 2.15 2.65-2.70 (double refractive -> “doubling”/fatamorgana effect)
Dispersion 0.060 0.104 (very strong)
Hardness 8 9.25
Density 5.95 3.22 (floats on methylene iodide, diamond sinks)
Comparison of properties of zirconia and moissanite