Name/Title
Quartz / BarreriteEntry/Object ID
2009.62.50Description
Chemical Composition: SiO2 / (Na,K,Ca)2 [Al2 S
Crystal System: Tetragonal System
Description: Common Name: Quartz / Barrerite
Chemistry: SiO2 / (Na,K,Ca)2 [Al2 Si2 O18] - 7H2O
Group: Silicate / Zeolite
Location: Alaska USA
Discription: Druzy white quartz with the rare bladded white barrerite crystals
PHYSICAL CHARACTERISTICS OF QUARTZ;
Color is as variable as the spectrum, but clear quartz is by far the most common color followed by white or cloudy (milky quartz). Purple (Amethyst), pink (Rose Quartz), gray or brown to black (Smoky Quartz) are also common. Cryptocrystalline varieties can be multicolored.
Luster is glassy to vitreous as crystals, while cryptocrystalline forms are usually waxy to dull but can be vitreous.
Transparency: Crystals are transparent to translucent, cryptocrystalline forms can be translucent or opaque.
Crystal System is trigonal; 3 2.
Crystal Habits are again widely variable but the most common habit is hexagonal prisms terminated with a six sided pyramid (actually two rhombohedrons). Three of the six sides of the pyramid may dominate causing the pyramid to be or look three sided. Left and right handed crystals are possible and identifiable only if minor trigonal pyramidal faces are present. Druse forms (crystal lined rock with just the pyramids showing) are also common. Massive forms can be just about any type but common forms include botryoidal, globular, stalactitic, crusts of agate such as lining the interior of a geode and many many more.
Cleavage is very weak in three directions (rhombohedral).
Fracture is conchoidal.
Hardness is 7, less in cryptocrystalline forms.
Specific Gravity is 2.65 or less if cryptocrystalline. (average)
Streak is white.
Other Characteristics: Striations on prism faces run perpendicular to C axis, piezoelectric (see tourmaline) and index of refraction is 1.55.
Associated Minerals are numerous and varied but here are some of the more classic associations of quartz (although any list of associated minerals of quartz is only a partial list): amazonite a variety of microcline, tourmalines especially elbaite, wolframite, pyrite, rutile, zeolites, fluorite, calcite, gold, muscovite, topaz, beryl, hematite and spodumene.
Best Field Indicators are first the fact that it is very common (always assume transparent clear crystals may be quartz), crystal habit, hardness, striations, good conchoidal fracture and lack of good cleavage
PHYSICAL CHARACTERISTICS OF BARRERITE:
Crystal System: Orthorhombic - DipyramidalH-M Symbol (2/m 2/m 2/m)
Cleavage: {???} Perfect
Color: White, Pink.
Density: 2.13
Diaphaneity: Transparent to Translucent
Hardness: 3-4 - Calcite-Fluorite
Luster: Vitreous (Glassy)
Streak: white
Fracture: conchoidal
Hardness: 7 Quartz
Luster: Vitreous
Occurrence: Quartz is an essential constituent of granite and other felsic igneous rocks. It is very common in sedimentary rocks such as sandstone and shale and is also present in variable amounts as an accessory mineral in most carbonate rocks. It is also a common constituent of schist, gneiss, quartzite and other metamorphic rocks. Because of its resistance to weathering it is very common in stream sediments and in residual soils.
Quartz occurs in hydrothermal veins as gangue along with ore minerals. Large crystals of quartz are found in pegmatites. Well-formed crystals may reach several meters in length and weigh hundreds of kilograms.
Barrerite, an extremely rare zeolite was found in large cavities on a tidal flat.
Rock Type: Sedimentary
Specific Gravity: 2.65 / 2.1
Streak: white
Variety: Quartz is the second most abundant mineral in the Earth's continental crust, after feldspar. It is made up of a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO2. It is also the most varied in terms of varieties, colors and forms. This variety comes about because of the abundance and widespread distribution of quartz..
Barrerite is a tectosilicate mineral and a member of the zeolite family. It is one of the rarer zeolites and found only at Rocky Pass, Kuiu Island, Alaska. It was named for Richard Maling Barrer (1910-1996), a British teacher born in New Zealand.Collection
RAGM Mineral CollectionAcquisition
Accession
2009.62Source or Donor
Museum Collection of MineralsAcquisition Method
DonationDimensions
Height
10-1/2 inWidth
2-3/4 inLength
9-1/2 inWeight
11.98 ozDimension Notes
Dimension taken at widest pointsLocation
Location
Display Case
DS-6Room
Delmar Smith HallBuilding
Crater Rock MuseumCategory
PermanentMoved By
Curtis GardnerDate
May 24, 2023Notes
Added current locationLocation
Container
CenterDrawer
BottomShelf
Right, RightWall
NorthRoom
Delmar Smith HallBuilding
Crater Rock MuseumCategory
PermanentMoved By
Steve MillerDate
July 11, 2012Location
Container
LeftDrawer
Top shelfShelf
Center, CenterWall
West wallRoom
Delmar Smith HallBuilding
Crater Rock MuseumCategory
PermanentMoved By
scottDate
September 19, 2009Location
Container
RightDrawer
TopShelf
LeftCabinet
case #41Wall
SouthRoom
Delmar Smith HallBuilding
Crater Rock MuseumCategory
Permanent