Chapter 6 Key Concepts & Terms Flashcards

1
Q

What is light?

A

Light is a form of radiant energy that travels in waves.

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2
Q

How does the energy of light relate to its wavelength?

A

Light of shorter wavelengths has higher energy than light of longer wavelength

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3
Q

What is visible light in relation to the electromagnetic spectrum?

A

Visible light is a small portion of the electromagnetic spectrum.

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4
Q

What is white light composed of?

A

White light is a combination of spectral colors.

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5
Q

What is the primary cause of color in diamonds?

A

Diamond color is primarily caused by defects in the crystal lattice.

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6
Q

What tools can gemologists use to observe a diamond’s absorption spectrum?

A

The spectroscope and spectrometer can help gemologists see a diamond’s absorption spectrum.

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7
Q

What causes most selective absorption-related gem colors?

A

Interaction of electrons with visible light causes most selective absorption-related gem colors.

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8
Q

Why are diamonds without color centers colorless?

A

Diamonds without color centers are colorless due to the lack of visible light absorption.

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9
Q

How do color-causing defects influence electron transitions within a diamond?

A

Color-causing defects works as energy “steps” within a diamond’s band gap to ease the electron transitions “fueled” by visible light absorption.

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10
Q

What is the most common cause of yellow color in diamonds?

A

Nitrogen-related defects are the most common causes of yellow color in diamonds.

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11
Q

What is the primary cause of green color in diamonds?

A

The most common cause of green color in diamonds is radiation

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12
Q

What characteristic is typically found in naturally irradiated diamonds?

A

Naturally irradiated diamonds usually contain areas of green or brown radiation damage on their surfaces or penetrating into the stones.

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13
Q

What impurity is responsible for the blue color in type IIb diamonds?

A

Boron impurities are responsible for blue color in type IIb diamonds.

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14
Q

What defect, caused by radiation, can create a blue color in diamonds with low nitrogen concentrations?

A

The GR1 defect, caused by radiation, can create blue color in diamonds with low nitrogen concentrations.

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15
Q

What is the main cause of color in pink-to-red diamonds?

A

Deformation-caused selective absorption is the main cause of color in pink-to-red diamonds.

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16
Q

What causes black, gray, and white colors in diamonds?

A

Inclusions are the main causes of black, gray, and white colors in diamonds.

17
Q

How does the energy level of luminescence compare to that of the radiation source?

A

The energy level of luminescence is lower than that of the radiation source

18
Q

Why is luminescence considered an efficient visual test for diamond identification?

A

Luminescence is an efficient visual test for diamond identification, it reveals hidden defects in the crystal lattice and can quickly distinguish between natural and synthetic diamonds.

19
Q

Definition of absorption spectrum?

A

A pattern of dark vertical lines or bands shown by certain gems when viewed through a spectroscope, or a linear graph recorded by a spectrometer.

20
Q

Definition of Band gap?

A

Energy difference between the valence band and the conduction band.

21
Q

Definition of Color center?

A

A defect that can influence an object’s absorption of visible light to cause its color.

22
Q

Definition of Colored lamellae?

A

Closely spaced grain lines where color concentrates.

23
Q

Definition of Electromagnetic spectrum?

A

The range of wavelengths of radiant energy extending from high energy to low energy, including visible light.

24
Q

Definition of Fluorescence?

A

Emission of visible light during stimulation by UV or X-ray radiation.

25
Q

Definition of Luminescence?

A

Emission of visible light by a material when it is exposed to a radiation source.

26
Q

Definition of Phosphorescence?

A

Continued emission of visible light after UV or X-ray stimulation stops.

27
Q

Definition of Selective absorption?

A

The process by which light not absorbed by a material returns to the observer.

27
Q

Definition of Wavelength?

A

The distance between two adjacent high or low points of a wave.

28
Q

Definition of Visible spectrum?

A

The range of wavelengths of visible light from 400nm (violet) to 700 nm (red)