Reference work entry
Jasper is also known as ‘bluish green stone’. It is a low-grade gem. Jasper generally refers to: (1) all bluish green or cyan precious or semi-precious stones; and (2) high-quality bluish green silicalite with other colours (e.g., green, red, orange, yellow and black) composed of quartz, chalcedony and iron oxide. The iron oxide and clay content can reach 20% or more, and it has a glassy and greasy lustre, can be opaque, slightly transparent to translucent, and has a Mohs hardness of 6.5–7, a density of 2.6 g/cm 3and several colours, such as dark red, green and mixed colours. Based on its colour and lustre, jasper can be divided into green jasper, yellow jasper, banded jasper, egg white jasper, agate jasper, sheep liver jasper and pig liver jasper. It is sometime described according to its unique patterns and colours, such as landscape jasper and blood drop jasper. Jasper is mainly a surface deposit of silica with several impurities. Some jasper is related to...
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