Tetradymit
Tetradymit
Tetradymit je vzácny telurid bizmutu.Tento minerál
kryštalizujúci v trigonálnej sústave, chemicky
sulfid-telurid bizmutitý – Bi2Te2S. Názov je z
grecštiny, tetra-štyri, didymos-dvojca.
Tetradymit casto vytvára štvorcatné zrasty, ktoré majú
vzhlad málo deformovaného štvorstenu. Jeho farba je
ocelovosivá, postupne mení farbu do žltkasta, neskôr až
do cierna. Zvycajne sa vyskytuje ako sprievodný minerál
hydrotermálnych ložiskách zlata.
Je to nepriehladný minerál s kovovým leskom. Je velmi krehký,má
nízku tvrdost (H = 1.5 - 2), stiepatelny (0001), kreslí na papier a
vyznacuje sa silnou fluorescenciou.
Tetradymit bol prvýkrát opísaný na Slovensku - nedaleko
Župkova v roku 1831.
Na konci 19. storocia tu robil rozsiahle prieskumné prace G.
Liszkay, našiel uz však len spomínanú zavalenú
štôlnicku. Všetky mladšie práce sa skoncili
negatívne, hoci vo výplavoch po šlichovaní sa našiel
zvýšený obsah bizmutu.
Do dnešných dní bolo z územia SR celkove opísaných a
uznaných 16 nových minerálov pre svet: cohenit, euchroit, evansit,
hauerit, hodrušit, kornelit, libethenit, mrázekit,
romboklas, rutil, schafarzikit, szomolnokit, telluronevskit,
tetradymit, vashegyit, vihorlatit.
Prístup ku
Keške
Keš Vás privedie k malej, dnes už zasypanej
štôlnicke na kopanici pod osadou Angeltovci. Práve tu bol
prvý krát popísaný tento vzácny minerál. Tetradymit sa tu nachádza
v rozložených andezitových tufoch
a v andezitových konglomerátov. Parkujte na (PARK) pri
miestnom pohostinstve 'Pohada PUB'..
Ak chcete logovat túto keš, odfotte sa s GPS (alebo alebo
len GPS) pred malou stolnou na zadanych koordinatoch (dobrovolne).
Tiež je potrebné zodpovedat nasledujúce otázky a odpovede
poslat cez e-mail bud mne cez profil, alebo Sleepy Ghost-ovi cez tento link:
- Ako tento minerál nazvali jeho prvý objavitel a aké je jeho
meno (informacná tabula) ?
- Ako sa predpoklada, ze tetradimit vznikol? (informacná
tabula).
Kes kludne logujte, nemusite cakat na potvrdenia spravnych
odpovedi.
Ak odpovede budu nespravne, alebo neuplne a pod., budem Vas
kontaktovat emailom. Pokial ale Vas email nepride do 3-och dni po
logu, log bez upozornenia mazem.
Buried
adit
Tetradymite
Tetradymite is a rare mineral consisting of bismuth, tellurium
and sulfide, Bi2Te2S, also known as telluric bismuth. If sulfur is
absent the mineral is tellurobismuthite and the formula is then
Bi2Te3. Traces of selenium are usually present.
Crystals are rhombohedral, but are rarely distinctly developed;
they are twinned together in groups of four; hence the name of the
mineral, from the Greek for fourfold. There is a perfect cleavage
parallel to the basal plane and the mineral usually occurs in
foliated masses of irregular outline. The color is steel-grey, and
the lustre metallic and brilliant.
The mineral is very soft (H = 1.5 - 2) and marks paper and has a
strong fluorescence.
Occurrence of Bi-Te mineralization of uncertain genesis and
origin. In highly altered andesite and its pyroclastic rocks,
tetradymite was locally found. Minor sulphidic mineralizations are
known from the surroundings.
At the end of 19.century, G Liszkay was doing the extensive
reserch, but he found burried adit only. All junjer researches
ended up in negative results, although he found increased content
of bismuth.
The type locality is Zupkov (Zsubko; Schubkau), Slovak Republic
where it was reported in 1831. It was first found, in 1815, at
Telemark in Norway. It often occurs in high temperature
hydrothermal quartz veins associated with native gold and in
contact metamorphic deposits.
Zdroj: en.wikipedia.org
Access to
the cache
Coordinates given are for small buried adit near settlement
'Angeltovci'. Tetradymite was first time described at thi place.
This rare mineral is distributed in andesite tuff and andesite
conglomerates. Park on coordinates given (PARK) near local pub
'Pohada PUB'.
To claim this cache you should take a photo of you with a GPS
(or your GPS only) in front of the entrance of small adit. You also
need to email me (via the link to my profile at the top of the page
or to Sleepy Ghost via this link) with the
answers to the following questions:
- What is the name of this mineral given to it by its first
discoverer and what is his name (information board) ?
- How is a apresumption, that tetradimit was created?
(information board).
Feel free to log this cache. You do not need to wait for
permission to log.
If your answers are not correct, incomplete etc., i will contact
you by e-mail. But if your e-mail is not comming to me within 3
days from your log, I will delete your log without notice.
Dakujem kešerovi Tajojo za tip na túto earthcache a za
vynikajúce podklady a materiály.