Slocum stone
Encyclopedia
Slocum stone is an early opal
simulant which was briefly popular prior to the introduction of synthetics and less expensive simulants. It was named after its inventor, John S. Slocum of Rochester, Michigan
.
John Slocum experimented during the 1960s with various methods. In 1971, he began marketing his first commercial simulant under the "Opal Essence" trade name. Not satisfied, he continued experimenting and in 1974 brought out the more realistic "Slocum Stone" type. However, Gilson synthetic opals and other imitation opals such as "Opalite
" came onto the market soon thereafter and greatly diluted the market for "Slocum Stone" By 1976, this product was being manufactured by MDI Corporation.
Slocum Stone is a silicate glass which shows traces of sodium
, magnesium
, aluminum and titanium
. It was manufactured in several base colors, and the opalescence
is produced by very thin layers of metallic film (estimated at 30 nanometres in thickness), in the form of translucent flakes, which produce a thin-film interference
effect. These flakes themselves lend color, along with colorant within the glass base. Bubbles and swirls typical of glass are other typical inclusions which may be noticed under magnification. In later examples, built-up laminations are visible when viewed from the side.
Opal
Opal is an amorphous form of silica related to quartz, a mineraloid form, not a mineral. 3% to 21% of the total weight is water, but the content is usually between 6% to 10%. It is deposited at a relatively low temperature and may occur in the fissures of almost any kind of rock, being most...
simulant which was briefly popular prior to the introduction of synthetics and less expensive simulants. It was named after its inventor, John S. Slocum of Rochester, Michigan
Rochester, Michigan
Rochester is an affluent city in north Oakland County in the U.S. state of Michigan on the northern outskirts of metro Detroit. The population was 12,711 at the 2010 census...
.
John Slocum experimented during the 1960s with various methods. In 1971, he began marketing his first commercial simulant under the "Opal Essence" trade name. Not satisfied, he continued experimenting and in 1974 brought out the more realistic "Slocum Stone" type. However, Gilson synthetic opals and other imitation opals such as "Opalite
Opalite
Opalite is a trade name for synthetic opalised glass and various opal simulants. It is also used to promote impure varieties of variously colored common opal....
" came onto the market soon thereafter and greatly diluted the market for "Slocum Stone" By 1976, this product was being manufactured by MDI Corporation.
Slocum Stone is a silicate glass which shows traces of sodium
Sodium
Sodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal and is a member of the alkali metals; its only stable isotope is 23Na. It is an abundant element that exists in numerous minerals, most commonly as sodium chloride...
, magnesium
Magnesium
Magnesium is a chemical element with the symbol Mg, atomic number 12, and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the Earth's crust and ninth in the known universe as a whole...
, aluminum and titanium
Titanium
Titanium is a chemical element with the symbol Ti and atomic number 22. It has a low density and is a strong, lustrous, corrosion-resistant transition metal with a silver color....
. It was manufactured in several base colors, and the opalescence
Opalescence
Opalescence is a type of dichroism seen in highly dispersed systems with little opacity. The material appears yellowish-red in transmitted light and blue in the scattered light perpendicular to the transmitted light. The phenomenon is named after the appearance of opals.There are different degrees...
is produced by very thin layers of metallic film (estimated at 30 nanometres in thickness), in the form of translucent flakes, which produce a thin-film interference
Thin-film optics
Thin-film optics is the branch of optics that deals with very thin structured layers of different materials. In order to exhibit thin-film optics, the thickness of the layers of material must be on the order of the wavelengths of visible light...
effect. These flakes themselves lend color, along with colorant within the glass base. Bubbles and swirls typical of glass are other typical inclusions which may be noticed under magnification. In later examples, built-up laminations are visible when viewed from the side.