Gemstone Chart |
Natural Andalusite Andalusite is popular as a collector stone but is seldom used in jewelry probably because of it's unavailability. With a hardness of 7 - 7.5 andalusite is tough enough to be used in jewelry. Andalusite, especially in the rough, can easily be confused with alexandrite because of similarities in color Categories: semi-precious stone Chemical Composition: Al2SiO5 Crystal Group: Orthorhombic Refractive Index: 1.628 - 1.647 Hardness: 7 - 7.5 Density: 3.13 - 3.21 Occurrence: Brazil, Sri Lanka, Spain, East Africa, Burma, U.S.A.
| Natural Clinohumite Clinohumite is a rare mineral and an especially rare gemstone. It is a member of the humite group of minerals, which includes humite, clinohumite, chondrodite, and norbergite.Only two sources of gem-quality material are known: the Pamir Mountains of Tajikistan, and the Taymyr region of northern Siberia. Color: Brown, yellow, white, orange, or reddish brown Categories: semi-precious stone Chemical Composition: Magnesium Silicate Fluoride OH Crystal Group: Monoclinic Refractive Index: 1.625 ¨C 1.668 Hardness: 6 - 6.5 Density: 3.17 - 3.35 Occurrence: Extremely rare - gem quality found only in the Pamir Mountains, Tadzhikistan. Other mineralogical occurrences include, Mt. Vesuvius, Italy; Pargas, Finland; Llanos de Juanar, Malaga, Spain; Tilly Foster Mine, New York; Fort Defiance, Apache County, Arizona; Crestmore Quarry, Riverside County and Lower Lake, Fresno County, California; Luna, New Mexico and Franklin, New Jersey, USA.
| Natural Sphalerite Sphalerite is one of the very few minerals that has a total of six directions of cleavage, and occurs in many different colors. It is an unusual rare gemstone which is craved for by people as it possesses more brilliance than diamonds. Color: Orange, yellow, brown, green Categories: semi-precious stone Chemical Composition: ZnS Crystal Group: Cubic Refractive Index: 2.37 Hardness: 3.5-4 Density: 4.05 Occurrence: Spain, Mexico
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