Type I and type II Diamond
A pure diamond is form with only one element that is carbon. Carbon atoms in the diamond lattice can be change with the atoms of elements like nitrogen and boron. These atoms are uniquely organize in a regular repeating pattern in the diamond lattice.
However, the other impurities can be soak up. Which can be classified by dividing the diamond types. As different diamond types react in different ways to enhance the diamond techniques. The diamond type is a scientifically classifies the level and the types of chemical impurities in the diamonds.
Basically, there are five types in which a diamond can be divide : Type IA, Type Ib, Type IIa, and Type IIb. The impurities can be measure in the crystal lattice of carbon atoms, unlike the inclusions. A single stone can exist in different types. Which can be determine by the infrared spectrum.
How Are The Diamonds Classified By Their Type?
In the 1930s the scientist began to recognize the types of diamonds which displayed similar features. The two main categories are Type I and Type II diamond on the basis of the transparency under the ultraviolet radiation. Later on, in 1959 the scientists discover that the principle chemical impurity in a diamond is the nitrogen. In which the Type I contained the impurity but the Type II didn’t.
According to the chemical build in the diamond classified the types. To determine the types the test were run to the stones and were administer by the GIA for the certification.
Classification of Diamond Types
The classification of diamond type is measured by the absence or presence of nitrogen. Which is the common impurity that is found in a diamond.
Type I Diamonds
The most common diamond class in nature is Type I. The Type I diamond contains nitrogen atoms within the diamond lattice as their main impurity. When a diamond is measured by IR absorption spectroscopy the Type I diamonds contains sufficient nitrogen. The Type I diamonds are also divide into Type Ia and Type Ib as both of them contains nitrogen, but the atoms are arrange differently in the diamonds.
Type Ia Diamonds
The compound element structure is most of the colorless stones are consider as the diamond class type Ia. The addition of nitrogen atoms are always cluster which appears throughout the stone. Type Ia diamonds are a combination of Type IaA, Type IaB & Type N3. The N3 here represents the group of three nitrogen atoms.
In Type Ia diamonds are 95% of the natural diamond and 0.3% are the impurities that are relatively widespread and clustered within the carbon lattice. This absorption of the nitrogen can cause to absorb the blue light to the diamond and making it appear into pale yellow or almost colorless. The compound elements which effects the color of the diamond by depending on. How the clusters in the diamond are broke down. After the break down the Type Ia is divide into two types:
Type IaA Diamonds
In Type IaA the nitrogen atoms don’t affect the color of the diamond as it is paired. These pairs of nitrogen atoms are also known as A-aggregates. The reason for not changing the color of Type IaA diamonds because it doesn’t absorb visible light.
Type IaB Diamonds
In Type IaB diamonds contain nitrogen atoms that are in large even-number aggregates. This impacts a yellow to brown tint in the diamonds. In Type IaB diamonds the four nitrogen atoms are called B-aggregates. Unlike, the Type IaA the Type IaB doesn’t absorb visible light.
Type Ib Diamonds
In Type Ib diamonds, nitrogen doesn’t occur in the adjacent lattice positions as the single nitrogen atoms. Replace the carbon atoms that are isolate in the lattice from one another. Type Ib contains 0.05% of nitrogen and makeup about 0.1% of all the natural diamonds. In the isolated sites the atoms have dispersed the atoms throughout the crystal and these impurities make it diffuse.
In Type Ib diamonds the singular form is opposed to the clusters by the nitrogen which are built within. Whereas, Type Ib diamonds are rarer than Type Ia diamonds. The Type Ib absorbs both of the blue and green lights which give an intense tone of the color presented in the diamond.
Type II Diamonds
The Type II diamonds doesn’t have any nitrogen impurities. Type II diamonds absorb the infrared of the different regions where it transmits in the ultraviolet. The Type II diamonds are made in extremely high pressure keeping it for longer periods. The Type II diamonds are found to be larger and harder. And the Type II diamonds are rarer than Type I diamonds.
Type II diamonds are also divided into two types:
Type IIa Diamonds
The Type IIa diamonds contain nitrogen and boron impurities which cannot be easily measured. Type IIa diamonds can be form only 1% or 2% of all-natural diamonds. The Type IIa diamonds have a lack of impurities and are usually colorless, transparent in the ultraviolet, and also have the highest thermal conductivity.
During the growth of tetrahedral crystal structure, the pressure and the tension can cause structural anomalies which leads to imperfections and can confer a brown, yellow, pink, red, purple hue. The Type IIa diamonds can have their structural repaired via High-Pressure High-Temperature (HPHT). The process of growing lab-grown diamond uses the CVD process which belongs to Type IIa.
Type IIb Diamonds
Whereas, the Type IIb diamond contains no IR-measurable nitrogen impurities in the structure of the lattice. The Type IIb diamonds seems to be unique because of the addition of boron impurity gives a blue tint within the stone. To all natural diamonds Type IIb makes about 0.1% and this makes it rarest and valuable in natural diamonds.
The boron causes the diamond to absorb the orange, yellow, and red light which lends to reflect the color of the diamond as grey or light blue in color. As a low level of boron impurities causes the diamond appears to be colorless. Unlike the other diamond types this the Type IIb is also p-type semiconductors.
Conclusion:
- Type-I represent 98% of all-natural diamonds and have the traces of nitrogen impurities and this makes it most common.
- Type–Ia tend to emit a yellowish tone as it contains nitrogen atoms throughout the crystal structure.
- Type-Ib are of 0.1% of all-natural diamonds which emits the orange, yellow, brown, and green tone to the diamond as they are all singular as opposed to clustered groups.
- Type–IIa are valuable and they contain little or no nitrogen impurities of all diamonds. It represents a 1% – 2% and are often form in the purple, pink or brown tone.
- Type IIb represent 0.1% of all diamonds as they contain the elements of boron within the structure.