According to historical records the diamond was one triangular in shape and crudely cut when it was bought by the merchant traveler, Jean Baptiste Tavernier. It changed hands several times in the ensuing years before it came into the Hands of Harry Winston, Inc who showed it at many exhibits and events around the world before donating it to the Smithsonian institution (Encylopedia Smithsonian 2008).
The hope diamond is 45.52 carats in weight and one of the most prominent examples of naturally doped semiconductors. It is due to the presence of traces of the element boron that the diamond has its blue color. The diamond has been categorized as VS1 which means that under a microscope it is seen to be faintly cloudy (Wisegeek 2009).
This blue color occurs due to the interaction of boron’s valence electrons with incoming light. Unlike metals which have characteristically unbound electrons, semiconductors have electrons which are continuously bound to atoms unless they are excited. When light strikes a semiconductor, the electromagnetic radiation from the visible light spectrum allows the electrons to drop from the conduction band thus releasing energy. The release of this energy causes a band gap which allows us to perceive a particular spectrum of light. However, to perceive this band a certain amount of energy is required to excite the electrons (Webexhibits 2009).
Boron is a Dopant which is an impurity in the carbon of this diamond. Dopants may contain more or less valence electrons than the semiconductor which allows the semiconductor to excite an electron to the band gap and cross the band gap respectively. Thus, in both cases less energy is required than a normal semiconductor for the electrons to get excited and emit their own particular band of light (Webexhibits 2009).
Thus, the hope diamond can be perceived to be blue since it only requires the thermal energy of a room to excite its electrons and normal white light. According to researchers all blue diamonds have phosphoresce bands which are centered at the 500 and 660 nm wavelengths. The color of this phosphorescence in the hope diamond is red (Physorg 2005; 2008).
An examination which has been conducted by a very sensitive colorimeter has shown that there is a slight violet component to the deep blue color of the diamond which cannot be seen by the naked eye. This violet component provides evidence of the original state of the diamond when it was found by Jean Baptiste Tavernier (Encylopedia Smithsonian 2008).
List of References
Encylopedia Smithsonian. (2008). The Hope Diamond. Web.
Physorg. (2008). Hope Diamond’s phosphorescence key to fingerprinting. Web.
Physorg. (2005). Researchers to Study Properties of the Hope Diamond. Web.
Webexhibits. (2009). What causes the color in blue diamonds and in LED lamps? (doped semiconductors). Web.
Wisegeek. (2009). What is the Hope Diamond? Web.