The two waves interfere with each other if they vibrate in the sale plane and travel along the same path. Retardation is the distance that one wave lags behind the other. This Retardation can be described either in terms of the number of wavelengths that one wave lags the other, or in terms of the […]

According to some authors, the human eye is constructed for the purpose of discriminating the different wavelengths of light. The perception of colors of light can be expressed according to their vacuum wavelengths. For instance, the light having vacuum wavelength of about 660 nm is perceived red, while those whose vacuum wavelength is about 600 […]

Light that comes directly from the sun or from an incandescent bulb is called an ordinary light. The kind of light from this light sources vibrates in all directions at right angles to the direction of propagation and is known to be unpolarized. Polarized light on the other hand has constrained vibration direction so that […]

Polarization of light may come in various ways and this is one of the areas concerned in optical mineralogy. A light can be polarized by selective absorption, double refraction, reflection, and scattering.
The basis of polarization with polarizing films is provided by the selective absorption. Tourmaline and a variety of other anisotropic minerals posses the property […]

The color of light that is not absorbed on transmission or reflection is making up the color of the mineral or of any other object that is of very concern in the field of optical mineralogy. Most of the time, when a mineral is evaluated both in reflected and transmitted light of the petrographic polarizing […]

Velocity
 
            The velocity of light is very dependent on the wavelength of light and on the nature of the material that it travels through. In a vacuum, the maximum possible velocity is 3.0 x 10exp10 cm/sec. The light usually slowed down when it enters any other medium. If why light slowed down is simply explained […]

Light is almost popularly known to bend when passing from one transparent material to another at any angle other than perpendicular to the boundary of the two materials. This is called the index of refraction or a measure of how effective a material is in bending light coming from a vacuum. This is simply referred […]

Electric and magnetic vectors, which vibrate at right angles to the direction of in which the radiation is moving are said to be constituted in all electromagnetic radiation including light. It is necessary to consider only vibration of the electric vector for mineral optics purposes. This is so because the behavior of the light is […]

It has been known that for all wavelengths of light, the index of refraction of a material is not the same. A good demonstration of this is by passing a white light through a prism. The more strongly refracted light is the light at the violet end of the spectrum. While the light at the […]

At least some light can enter the higher-index material regardless of the angle of incidence when light travels from a low index-mineral to a higher-index one. But then this statement may not always hold true for those light going from a high-index material to a low-index material where the angle of refraction is larger than […]