Carboniferous and Devonian (Old Red Sandstone) igneous and sedimentary rocks predominate in this area
of central Scotland, covering Ayrshire and Lanarkshire.
Coal-mining had an important role in the past.

Numerous Tertiary dykes, or "dyke-swarms", trending NW-SE from the Tertiary volcanic centres of Mull, Skye, Rhum and Ardnamurchan on the north-west coast
of Scotland also traverse the area.

Several of these dykes stretch much farther south
into northern England. Indeed, some individual dykes,
given their particularly distinctive mineral composition,
can also be traced over this length.

Scotland's own ophiolite zone - where there is some geological evidence of Scotland and England, once apart, coming together in Palaeozoic times - can be found on the south Ayrshire coast at Ballantrae.

BARITE - Swinlees Mine, Kilbirnie, Ayrshire.
Crystals to 8mms.

Mineralization in the area is generally on a small scale. Some old limestone quarries in northern Ayrshire have rendered some specimens of strontianite, barite and celestite with occasional fluorite - something of a Scottish rarity.

In the past, coalmines have yielded very good millerite specimens too. An uncollaborated diamond find in these mines was once reported, but is probably an error.

Close to the ophiolite zone at Ballantrae, around Lendalfoot and Colmonell, pectolite and chrome spinel occur.

The Leadhills mining area, in the southern part of Lanarkshire, is dealt with separately (see link below).

In Ayrshire, there are several occurences of agates, particularly on the coast. Other smaller, more restricted occurences can be found inland also, including Burn Anne, near Galston. (see agates).

Some sites are on restricted areas (SSSI - Sites of Special Scientific Interest) created to protect early fossil fish occurences in rocks of Devonian age.

In Lanarkshire and Ayrshire, in the Lesmahagow, Muirkirk and Sorn area, iron and barite veins have occasionally
given specimens of botryoidal hematite of some interest.

BARITE

Swinlees Mine, Kilbirnie, Ayrshire.
Smoky blue-grey prisms in parallel growth to 1cm.

HEMATITE
Auchinlongford Mine, Sorn, Ayrshire
(Botryoidal "Kidney Ore" habit (65x60mms).

HEMATITE
Mannoch Hill Mine, near Lesmahagow, Lanarkshire
Botryoidal "Kidney Ore" habit (65x45 mms).

Next to the Southern Upland Fault in southern Ayrshire,
at Hare Hill (Knipe Mine), near New Cumnock,
there is an occurence of stibnite.

The mineral occurs as masses of elongated, silvery blades to several centimetres embedded in quartz veins.
Some of the stibnite crystals may be altered, either partially or entirely, to stibiconite.

At Lugar, a former coal-mining community in south Ayrshire, the less common amphibole group mineral, kaersutite, can be found as embedded crystals in the rock termed lugarite (a type of ijolite), which comprises part
of a local Carboniferous sill complex.

From a small and insignificant copper trial near Kilbirnie (Swinlees Mine), in Ayrshire, a limited number of specimens of smoky, blue-grey and colourless-white,
barite crystals have been extracted.
Crystals can attain up to 25mms and over.

GROSSULARITE - Loanhead Quarry, Beith, Ayrshire.
A group of transparent, gemmy crystals to 1mm
resting on a pale grey-green, fibrous amphibole mineral.

The most interesting site of recent years in the region is Loanhead Quarry, near Beith in northern Ayrshire.

Good hand specimens of calcite and particularly of botryoidal prehnite were found. The site was also a good location for micromounters - with several species occuring well-crystallised on a single specimen.

Examples of several zeolite species, particularly thomsonite and analcime, associated with garnets, hematite and epidote... have made excellent micromounts.

The mineralization is associated with a dyke, belonging to one of the "swarms" mentioned earlier.

The site is interesting for the uncommon association of zeolite members with garnet species. Both andratite and grossularite garnet are present.

The rare species, greenockite, has also been recorded
at the locality, as well as descloizite and vanadinite micro-crystals.

* (this site is currently not accessible).

THOMSONITE - Loanhead Quarry, Beith, Ayrshire.
3mm bladed crystal piercing calcite crystals on a garnet-rich matrix.

PREHNITE - Loanhead Quarry, Beith, Ayrshire.
Crystalline botryoidal aggregates with calcite. (spec: 60x30mms).

"CHROMITE" (Chrome Spinel)
Colmonell, Ayrshire.
"Leopard Ore". Black chrome spinel aggregates in dunite matrix. (100x80mms).