Diamonds Classification and their impurities

Pure diamonds are composed entirely of carbon.  However, diamond crystals contain minute quantities of trace elements that can take the place of some carbon atoms and the most common form is nitrogen.

A trace element is a an element that occur in minute quantities.  Because of their impurities, diamonds are classified into two types.  Type I and Type II.

Type I - Nitrogen occur as the major impurity up to 0.2%.
Type II - Do not contain nitrogen as a significant impurity. Type II diamonds also contain nitrogen but does not affect the physical properties.

Diamonds with large concentration of nitrogen impurities start with a single isolated atom. Due to the geological condition of heat and pressure over time, the nitrogen migrate thru the structure to form pairs and then aggregates of there or four nitrogen atoms which are Ia.

Type Ib transform into Type Ia.


The majority of natural diamonds are Type Ia.

Type Ia diamonds are diamonds that contain nitrogen atoms as pairs or small groups called aggregates.

Type IaA- diamonds contain aggregates of 2 nitrogen atoms

Type IaB -  or groups of 3 or 4 nitrogens called aggregates with vacancies.  Groups of 3 surrounding a vacancy are called N3 color centers.

Electromagnetic Spectrum

The electromagnetic spectrum is the range of all possible frequencies of electromagnetic radiation.The "electromagnetic spectrum" of an object has a different meaning, and is instead the characteristic distribution of electromagnetic radiation emitted or absorbed by that particular object.

The electromagnetic spectrum extends from below the low frequencies used for modern radio communication to gamma radiation at the short-wavelength(high-frequency) end, thereby covering wavelengths from thousands of kilometers down to a fraction of the size of an atom. The limit for long wavelengths is the size of the universe itself, while it is thought that the short wavelength limit is in the vicinity of the Planck length,although in principle the spectrum is infinite and continuous.

Most parts of the electromagnetic spectrum are used in science for spectroscopic and other probing interactions, as ways to study and characterize matter. In addition, radiation from various parts of the spectrum has found many other uses for communications and manufacturing (see electromagnetic radiation for more applications).

Luminescence

Luminescence  - describes emission of cold non incandescent light by a substance. A type of luminescence is fluorescence and phosphorescence.

Color Centers

Color Centers are defects in the crystal structure that absorbs light.  These defects may occur during growth, or by irradiation.  This irradiation may be natural or artificial.


Examples of color centers include:
Vibronic occur centers such as that in type IaA/B diamonds.

Type II Diamonds

Type II diamonds have no significant amount of nitrogen

Type IIa - contain no significant impurities. Pure Type IIa diamonds have no sharp absorption in the visible region.
Type IIa diamonds which are capable of conducting electricity

Type IIb - boron atoms are present as an impurity
Type IIb diamonds which are not able to conduct electricity.

Type I Diamonds

Type Ia - Nitrogen atoms are present as pairs or small groups called aggregates
Type Ib - Nitrogen atoms are present as isolated atoms

Type IaA - Contain aggregates of two nitrogen atoms, A aggregates
Type IaB - Nitrogen is present as aggregates of four nitrogen toms surrounding a 'vacancy' B aggregates. (Most diamonds containing some nitrogen in the B form also have aggregates of three nitrogen atoms surrounding a vacancy.


It is common to find many diamonds with a mixture of A and B aggregates. These are described as type IaA/B or IaAB.  Type IaAB - Contain both the A and B forms of nitrogen

Birefringence

Birefringence is the optical property of a material having a refractive index that depends on the polarization and propagation direction of light.

Polarization is a property of waves that can oscillate with more than one direction.

Volcanoes

A volcano is a rupture) on the crust) of a planetary mass object, such as the Earth, which allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface.
Earth's volcanoes occur because the planet's crust is broken into 17 major, rigid tectonic plates that float on a hotter, softer layer in the Earth's mantle. Therefore, on Earth, volcanoes are generally found where tectonic plates are diverging or converging. For example, a mid-oceanic ridge, such as the Mid-Atlantic Ridge, has volcanoes caused by divergent tectonic plates pulling apart; the Pacific Ring of Fire has volcanoes caused by convergent tectonic plates coming together. Volcanoes can also form where there is stretching and thinning of the crust's interior plates, e.g., in the East African Rift and the Wells Gray-Clearwater volcanic field and Rio Grande Rift in North America. This type of volcanism falls under the umbrella of "plate hypothesis" volcanism. Volcanism away from plate boundaries has also been explained as mantle plumes. These so-called "hotspots", for example Hawaii, are postulated to arise from upwelling diapirs with magma from the core–mantle boundary, 3,000 km deep in the Earth. Volcanoes are usually not created where two tectonic plates slide past one another.

Extinct Volcanoes

An active volcano is a volcano that has had at least one eruption during the past 10,000 years. An active volcano might be erupting or dormant.

An erupting volcano is an active volcano that is having an eruption...

A dormant volcano is an active volcano that is not erupting, but supposed to erupt again.

An extinct volcano has not had an eruption for at least 10,000 years and is not expected to erupt again in a comparable time scale of the future.

 

Extinct Volcano

There are three ways to describe a volcano’s activity; there can be active, dormant, or extinct volcanoes. Active volcanoes have erupted recently. A dormant volcano isn’t erupting right now, but vulcanologists expect it could erupt at any time. Extinct volcanoes haven’t erupted for tens of thousands of years, and aren’t expected to erupt again.

What causes volcanoes to go extinct? Simply put, they’re cut off from their supply of lava. This is where a chamber of magma underneath the surface of the Earth finds its way to the surface through weaknesses in the crust. A good example of this is the hotspot that created the chain of Hawaiian Islands. The tectonic plate carrying the islands is slowly moving, so that volcanoes are cut off from the hotspot underneath. Eventually they go extinct, while the hotspot creates a new volcano further to the East.

Some volcanoes look extinct, but it might just be a long time since they’ve erupted. For example, the Yellowstone Caldera in Yellowstone National Park hasn’t had a violent eruption in about 640,000 years, but scientists think it’s still active. There has been minor activity and lava flows as recently as 10,000 years ago. The region also has regular minor earthquakes and ground is lifting up in some areas, so scientists think that’s it’s still an active volcano.

 

Crystals and Color

How do crystals get their color? The presence of different chemicals causes the variety of colors to different gemstones. Many gems are simply quartz crystals colored by the environments to which they are exposed. Amethyst gets its color from iron found at specific points in the crystalline structure. Topaz is an aluminium silicate - it comes in many colors due to the presence of different chemicals. The color of any compound (whether or not it is a crystal) depends on how the atoms and or molecules absorb light. Normally white light (what comes out of light bulbs) is considered to have all wavelengths (colors) of light in it. If you pass a white light through a colored compound some of the light is absorbed (we don't see the color which is absorbed, but we see the rest of the light) as it is reflected off the surface. This gives rise to the idea of "Complementary Colors". If a compound absorbs light of a certain color the compound appears to be the complimentary color. Here is a table of colors and their compliments:

So if you have a crystal which absorbs red light, it will appear green and if the crystal absorbs green light, it will appear red.

Molecule

Molecule - a group of atoms bonded together, representing the smallest fundamental unit of a chemical compound that can take part in a chemical reaction.


Molecules form when two or more atoms form chemical bonds with each other. It doesn't matter if the atoms are the same or are different from each other.

Molecules Versus Compounds Molecules made up of two or more elements are called compounds. Water, calcium oxide, and glucose are molecules that are compounds. All compounds are molecules; not all molecules are compounds.

What Is Not a Molecule?Single atoms of elements are not molecules. A single oxygen, O, is not a molecule. When oxygen bonds to itself (e.g., O2, O3) or to another element (e.g., carbon dioxide or CO2), molecules are formed.

What is a Mineral

Minerals can not be grown. Minerals are mined. Minerals are an energy source. Any naturally occurring inorganic substance having a definite chemical composition and characteristic crystalline structure, color, and hardness. There are approximately 4000 varieties of minerals which can be classified into one of eight major mineral classes similar to how biologists classify living organisms into groups such as plants, animals, fungi, and bacteria.

Mineral Classification
Minerals, however, are classified into groups by their composition and crystal structure. Ninety five percent of the rocks found in Earth’s crust contain minerals known as silicates. Silicates are the most abundant minerals and make up about 25% of all known minerals. The structure of all silicates is based on a silicon atom surrounded by four oxygen atoms. Silicates can be further classified into six subclasses differentiated by their structure. Common silicates include quartz, feldspars, pyroxene and olivine.

What is an Atom

An atom is the smallest unit of a chemical element.  It is a fundamental piece of matter.  A matter is anything that can be touched physically. Everything in the universe is made of matter except energy. So everything in the universe is made up of atoms.

An atom is made out of particles called subatomic particles: protons, neutrons, and electrons.

The electrons which are negatively charged fly around or orbit the nucleus which in the center of the atom and consists of the protons and neutrons which are negatively charged. Typically, the number of electrons and protons are equal.

Carbon element has 6 elections, 6 protons and 6 neutrons.

The negative electrons are attracted to the positive nucleus by the same electrical force which causes magnets to work. That's what keeps the atom together.

What is a crystal and how is it formed?

A crystal is a solid geometric structure of a repeating pattern of molecules connecting it together. In crystals, a unit cell is repeated in exactly the same arrangement over and over throughout the entire material.

Crystals grow by a process called "nucleation". Nucleation can start with assisted nucleation or unassisted nucleation. It will continue to grow until an equilibrium is reached.

Why crystals grow at different rates in different directions is a very complicated question. If there is a highly attractive interaction (energetically speaking) along a certain direction of a crystal, then that direction will probably grow fast. However, it could also grow slowly, if that direction interacted strongly with the solvent; having strongly absorbed solvent on the surface of the crystal could block growth.

Refraction and Refractive Index

When light enters a liquid or solid substance from air its speed is greatly reduced. This bending effect is called refraction. Different substances slow the light to different speeds.

The more the light is slowed when it enters the material, the more the material will bend the light (the greater amount of refraction). Different materials tend to give different results for this refraction.

We can think of this as the optical density: the greater the slowing effect, the greater the optical density of the material. The greater the optical density, the greater the refractive power. It's too difficult to measure the speed of light through air, instead we measure it's bending effect.

Refraction is the change in direction in which light travels when it passes from one medium into another of differing optical density.

The Refractive Index of a diamond is 2.42 compared to quartz which is 1.54-1.56. Refraction is an important optical effect cause it has a diagnostic value. Refraction has a direct relationship to other optical properties such as reflection and brilliance.

Refractive Index is a number that describes how light propagates through that medium. The refractive index determines how much light is bent, or refracted, when entering a material.