ESCR - Greenan Mountain - Mineralogy

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Summary Full report
Greenan Mountain - Mineralogy	Tyrone

Site number:	559
ESCC:	EO
Locality Type:	Stream section	Status:	local interest
Grid Reference:	H310686 Approximate
Google maps:	54.56521,-7.52074
County:	Tyrone	Council area:	Fermanagh & Omagh District Council
Period:	Precambrian
Stages:	Dalradian

Site Description
Greenan Mountain, near Lack, Co.Tyrone: old lime kiln near fuchsite locality.
Highlights:
Chromium-bearing muscovite (fuchsite) in dolomitic schist.
Introduction:
This site is located about 4km northeast of Lack village, c.1km north of Greenan Mountain in a small, steeply incised stream valley c.300m upstream of its confluence with the main river.
Description:
Greenan Mountain, near Lack, Co.Tyrone: fuchsite outcrop. On the south side of the valley 100m upstream of an old lime kiln at a forestry track, are exposures 2-3m wide by 1m high of an unusually bright green-coloured schist. Greenan Mountain, near Lack, Co.Tyrone: fuchsite schist. The colour is due to the presence of the chrome-muscovite mineral, fuchsite, which occurs in a foliated dolomitic mica schist. Nearby exposures are of graphitic dolomite mica schist and dolomite rock (hence the lime kiln). These lithologies form part of the Lack Inlier of Dalradian metasedimentary rocks.
Importance:
To the author’s knowledge this is the only occurrence of fuchsite in Northern Ireland. Fuchsite is often associated with gold mineralization, either as a gangue mineral in vein deposits or in the altered host rocks, as in the Mother Lode deposit in California and the Cregganbaun gold prospect in County Mayo. Its discovery at Greenan Mountain, by prospectors working for Riofinex in the 1980s, was an incentive to gold exploration in the Lack inlier. However, to the authors’ knowledge, gold anomalies are not directly associated with this particular occurrence.
Conclusions:
The site is considered mineralogically interesting but not worthy of designation.
Notes:
See also Key Site 247 - Greenan Mountain Stream.

Keywords
Minerals:	Dolomite, Fuchsite, Graphite
Rocks:	Schist

Measurements
Length:		Width:	2-3m	Height:	1m
Depth:		Area:

Uses
Uses:	Forest.


Record type:	ESCR report	Recorded by:	R. Nawaz and N.R. Moles
Entered by:	E M Porter
Last updated:	07 MAY 68

Enlander, I., Dempster, M. & Doughty, P., 2026. Greenan Mountain - Mineralogy, County Tyrone, site details. [In] Earth Science Conservation Review.
https://www.habitas.org.uk/escr/site.php?item=559. Accessed on 2026-11-06.

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