Help mindat.org|Log In|Register|
Home PageMindat NewsThe Mindat ManualHistory of MindatCopyright StatusManagement TeamContact UsAdvertise on Mindat
Donate to MindatSponsor a PageSponsored PagesTop Available PagesMindat AdvertisersAdvertise on Mindat
Minerals by PropertiesMinerals by ChemistryAdvanced Locality SearchRandom MineralSearch by minIDLocalities Near MeSearch ArticlesSearch GlossaryMore Search Options
Search For:
Mineral Name:
Locality Name:
Keyword(s):
 
The Mindat ManualAdd a New PhotoRate PhotosLocality Edit ReportCoordinate Completion ReportAdd Glossary Item
StatisticsThe ElementsMember ListBooks & MagazinesMineral Shows & EventsThe Mindat DirectoryHow to Link to MindatDevice Settings
Photo SearchPhoto GalleriesNew Photos TodayNew Photos YesterdayMembers' Photo GalleriesPast Photo of the Day Gallery

Faden Quartz

This page is currently not sponsored. Click here to sponsor this page.
Formula:
SiO2
Name:
From "Faden", German for "thread". Pronounced "fah-den".
A variety of Quartz

"Faden quartz" is the anglicized version of the German "Fadenquarz". "Faden" (pronounced "fah-den") means "thread" and refers to a white line that runs through the crystal.

Faden quartz forms in fissures in the host rock that widen slowly and steadily.
Quartz crystals inside the host rock will rupture when the fissure opens. In a silica rich solution, this rupture will heal quickly, forming a crystal that is attached to the opposing rock walls and bridges the new opening. While the fissure continues to open steadily, the crystal will also continue to crack and heal. Because growth is much quicker on fractured surfaces than on regular faces and because it leads to small regular faces on the opposite conchoidal fracture surfaces that do not perfectly match, some of the growth solution is included in the crystal. The repeated rupturing and healing leaves a scar of liquid and gas inclusions in the crystal: a white thread, the "faden". In rare cases, the faden is covered by chlorite, which demonstrates beautifully that a now platy specimen did indeed start as a thin thread (see third head photo).

The thread can be seen best in crystals that grew parallel to the wall, because the speed of growth is usually larger along the crystals c-axis (from tip to tip). These faden quartzes usually assume a platy shape. Faden quartz crystals that grew perpendicular to the walls, so that the tips point to the rock wall, do not get platy. The thread is usually straight, but depending on the movement of the opposing rock walls, may also be curved, jagged or interrupted.

Faden quartz occurs in extension fissures in different environments, most commonly in Alpine-type fissures. They often form curtain-like groups of intergrown crystals.



Hide all sections | Show all sections

Chemical Properties of Faden QuartzHide

Formula:
SiO2

Other InformationHide

Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

References for Faden QuartzHide

Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Laemmlein, G.G. (1946) O proischoschdenii ploskich kwarzew s «beloj polosoj». Wopr. Mineral. Geochim. Petrogr. (Isdat. Akad. Nauk SSSR, Moskwa): 98-110.
Richards, R.P. (1990) The Origin of Faden Quartz. Mineralogical Record: 21: 191-201.
Rykart, R. (1995) Quarz-Monographie - Die Eigenheiten von Bergkristall, Rauchquarz, Amethyst, Chalcedon, Achat, Opal und anderen Varietäten. Ott-Verlag, Thun.

Internet Links for Faden QuartzHide

Mineral and/or Locality  
Mindat.org is an outreach project of the Hudson Institute of Mineralogy, a 501(c)(3) not-for-profit organization.
Copyright © mindat.org and the Hudson Institute of Mineralogy 1993-2017, except where stated. Mindat.org relies on the contributions of thousands of members and supporters.
Privacy Policy - Terms & Conditions - Contact Us Current server date and time: September 21, 2017 07:55:16 Page generated: August 24, 2017 02:53:01
Go to top of page