Name/Title
Bruneau JasperEntry/Object ID
2015.1.12Description
Chemical Composition: SiO2
Crystal System: Hexagonal System
Description: Common name: Jasper var.Bruneau
Composition : SiO2
Group: Silicates
Location: Bruneau,Idaho
Description: This is a large specimen which has the classic appearance of Bruneau Jasper. It has a cream colored, fortified agate center surrounded by reddish brown. There is one section of a translucent grey,striped agate. Rock is brecciated and tan in color.
Physical Characteristics: The appeal of Jasper is its interesting color patterns and formations. Though it can be a solid color, it is most often mottled, spotted, ringed, or striped. Each Jasper has a unique color or pattern, lending this gemstone much variety. Jasper is an ancient gemstone, and is mentioned in the bible and other classical sources. Though fairly common and affordable today, Jasper in antiquity was regarded as a valuable stone. USES Jasper is generally an inexpensive gemstone when used in jewelry. It is cut and polished into cabochons, and used as beads for necklaces and bracelets. It is also carved into cameos which can be worn as pendants.
Jasper is an opaque,[1] impure variety of silica, usually red, yellow, brown or green in color. Blue is rare. This mineral breaks with a smooth surface, and is used for ornamentation or as a gemstone. It can be highly polished and is used for vases, seals, and at one time for snuff boxes. When the colors are in stripes or bands, it is called striped or banded jasper. Jaspilite is a banded iron formation rock that often has distinctive bands of jasper. Jasper is basically chert which owes its red color to iron(III) inclusions. The specific gravity of jasper is typically 2.5 to 2.9.[2]
Fracture: Conchoidal
Hardness: 7 Quartz
Luster: Vitreous
Rock Origin: Post-depositional
Rock Type: Igneous
Specific Gravity: 2.7
Streak: White
Variety: Jasper is an opaque rock of virtually any color stemming from the mineral content of the original sediments or ash. Patterns arise during the consolidation process forming flow and depositional patterns in the original silica rich sediment or volcanic ash. Hydrothermal circulation is generally thought to be required in the formation of jasper.
Jasper can be modified by the diffusion of minerals along discontinuities providing the appearance of vegetative growth, i.e., dendritic. The original materials are often fractured and/or distorted, after deposition, into myriad beautiful patterns which are to be later filled with other colorful minerals. Weathering, with time, will create intensely colored superficial rinds.
The classification and naming of jasper presents an enormous challenge. Terms attributed to various well-defined materials includes the geographic locality where it is found, sometimes quite restricted such as "Bruneau" (a canyon) and "Lahontan" (a lake), rivers and even individual mountains, many are fanciful such as "Forest Fire" or "Rainbow", while others are descriptive such as "Autumn", "Porcelain" or "Dalmatian". A few are designated by the country of origin such as a Brown Egyptian or Red African leaving tremendous latitude as to what is called what. Then there are inappropriately named materials, for example "Ocean Jasper" from Madagascar which is really a chalcedony, as is Bloodstone from India.
Picture jaspers exhibit combinations of patterns (such as banding from flow or depositional patterns (from water or wind), dendritic or color variations) resulting in what appear to be scenes or images, on a cut section. Diffusion from a center produces a distinctive orbicular appearance, i.e., Leopard Skin Jasper, or linear banding from a fracture as seen in Leisegang Jasper. Healed, fragmented rock produces brecciated (broken) jasper. Examples of this can be seen at Llanddwyn Island in Wales.Collection
Delmar Smith Mineral CollectionDimensions
Width
6 inDepth
3-1/4 inLength
6-1/2 inLocation
Location
* Untyped Location
DS-11Room
Delmar Smith HallBuilding
Crater Rock MuseumCategory
ExhibitMoved By
Ian C.Date
January 21, 2025Notes
USA Case InstallationLocation
Display Case
DS-10Room
Delmar Smith HallBuilding
Crater Rock MuseumCategory
PermanentMoved By
Curtis GardnerDate
May 10, 2023Notes
Added current location while cleaning shelf