A Brief History of Iolite Gemstones
The name “iolite” is derived from the Greek word for violet. Dichroite is another old name that is still being termed for this variety at these times. It is a Greek word which to a degree has a meaning of “two –colored rock,” which was such a character to the compound cordierite’s solid pleochroism.
Physical Properties of Iolite Gemstones
Iolite (gemology) or cordierite(mineralogy) is mainly composition of magnesium aluminum silicate. Due to the variety iolites, the majority of precious stones are used within gemstone jewelry.
Iolites crystallize structure is a orthorhombic system and has crystals that have transparent and translucent characteristics. The gemstone is typically blue, violet, gray, and can be shades of brown. The color is very much pleochroic, in which it transmits different colors when viewed in different axes and when being rotated can alter from the color blue –violet to the yellowish gray color. Iolite is also called as water sapphire or diochroite. Gem quality iolite typically varies in color formations from a sapphire blue to indigo to gray of a particular yellow shade, as stated, to light blue as the angle of the stroke of light changes.
Cordierite has hardness between 7 and 7.5 on the Mohs scale and specifically has a relative density of 2.4 to 2.7. Iolites usally have an uneven conchoidal or a shell–shaped fracture and had a glossy and a vitreous luster. As a pleochroism, it can be resembled by quartz. It can also be distinguished from corundum by its lowered hardness. Indialite contains the same type of crystalline structure with beryl.
Iolites particularly consists of an alumino silicate tetrahedral structure and is are made up of rings of six tetrahedrons. These rings are associated with magnesium atomic particles which are chained to six oxygens. The rings are aligned to form large channels and a framework, these large channels may be tied up by existing molecules such as carbon dioxide, methane, and even water. For a clear picture of this click here
Naturally, iolite has similar properties to shale, in which are fine–grained sedimentary rocks formed by the consolidation of layers of mud or clay. The best varieties of iolites found mostly on Sri Lanka and most parts of India and South Asia, Burma, Brazil, the northern territories of Australia, the State of Connecticut in the U.S., Namibia, Tanzania, Madagascar, Yellowknife area of the Northwest Territories of Canada.