mineral specimens
rare minerals
mineral dealer
systematic minerals
Black Hills minerals
fine minerals
mineral dealer
Dana minerals
IMA minerals
mineral collections
rock and minerals
gem crystal
0 item @ $0.00  

Mineralpedia Details for Sylvanite

Reset

Sylvanite

Sylvanite

Named for the locality where it was first found in Transylvania (sylvan) in Romania and also for its tellurium content as an early name suggested for tellurium was sylvanium. Sylvanite occurs in hydrothermal veins of low temperature but can also be found as one of the last-formed minerals in medium-temperature to high-temperature deposits as well.  It is present in small amounts in hundreds of gold-silver deposits, but not typically as rich specimens or as an economically viable mineral. Sylvanite is a light sensitive mineral and can tarnish darkly if exposed to light for long periods.

Ref. Handbook of Mineralogy, Anthony et al (1995) and MSA at http://www.handbookofmineralogy.org/pdfs/sylvanite.pdf

Formula
AgAuTe4 
Crystal System
Monoclinic 
Crystal Habit
Prismatic, Skeletal, Platy 
Cleavage
Perfect, None, None 
Luster
Metallic 
Color
yellowish silver white, white 
Streak
steel gray 
Class
Monoclinic - Prismatic 
Fracture
Uneven 
Hardness
1.5-2 
WebMineral
View Sylvanite 
Mindat
View Sylvanite 

Sylvanite from Sacarîmb (Nagyag in Hungary), Romania

Sylvanite
            from Sacarîmb (Nagyag in Hungary), Romania

Arborescent crystal growth with individual crystals from 5 to 10mm.

Click thumbnail images for larger view.

Sylvanite from Portland mine, Lawrence Co., South Dakota, United States

Sylvanite
            from Portland mine, Lawrence Co., South Dakota, United States

Streaks and this sheets to 1cm.

Click thumbnail images for larger view.

Sylvanite from Cresson mine, Cripple Creek, Teller Co., Colorado, United States

Sylvanite
            from Cresson mine, Cripple Creek, Teller Co., Colorado, United States

Numerous brassy gold, striatated and tabular crystals of Sylvanite up to 4mm,

Click thumbnail images for larger view.

Sylvanite from Emperor mine, Tavua Gold Field, Viti Levu, Fiji

Sylvanite
            from Emperor mine, Tavua Gold Field, Viti Levu, Fiji

This is a very rich specimen with a few dozen or more sharply terminated, goldish prismatic Sylvanite crystals, the largest of which is 4mm.

Click thumbnail images for larger view.

Sylvanite from Spotted Horse mine, Fergus Co., Montana, United States

Sylvanite
            from Spotted Horse mine, Fergus Co., Montana, United States

Here's a telluride locality, which you may not have heard of. The specimen is very rich with goldish platy Sylvanite 2-3mm wide.

Click thumbnail images for larger view.

All photos by Dakota Matrix and are Copyrighted © and may not be used without permission. Copyright © 2019 - Dakota Matrix Minerals, Inc. Privacy | Terms & Conditions | Site Map