Difference between revisions of "Jasper"
From The Gemology Project
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[[Image:P1040038.JPG|thumb|left|240px|Guadalupe poppy jasper slab.]] | [[Image:P1040038.JPG|thumb|left|240px|Guadalupe poppy jasper slab.]] | ||
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+ | [[Image:Mhpj2.JPG|thumb|left|240px|Morgan Hill poppy jasper cab.]] | ||
+ | [[Image:Mhpj3.JPG|thumb|left|240px|Morgan Hill poppy jasper. Details of the orbicular structures.]] | ||
+ | [[Image:Mhpj1.JPG|thumb|left|240px|Morgan Hill poppy jasper slab.]] |
Revision as of 02:21, 20 May 2011
Jasper | |
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Chemical composition | SiO2 Silicon dioxide |
Crystal system | Trigonal |
Habit | Aggregate, massive |
Fracture | Conchoidal |
Hardness | 6.5-7 |
Refractive index | 1.53-1.54 |
Specific gravity | 2.58-2.64 |
Lustre | Vitreous |
Scenic jasper
Picture, or scenic, or landscape jasper and agate gets its name from the pictures of scenes, animals or objects formed by the colorful patterns from other minerals present.
Poppy Jasper
"Poppy Jaspers" are jaspers showing red orbicular patterns resembling poppies, hence the name. The best varieties come from Northern California, close to the S. Andreas Fault system (Morgan Hill and Guadalupe).