Dark coloured monzonite has been produced for monumental stone and building purposes from two small quarries at the north end of a northwest trending ridge close to the derailing switch along the railway line east of Rossland. The quarries are developed in the Early Jurassic Rossland monzonite, an east-trending monzonite stock 8 kilometres long with a width of up to 3 kilometres.

The monzonite consists of dark greenish glistening hornblende phenocrysts up to 8 millimetres in diameter and smaller black glistening mica flakes set in a light coloured matrix of orthoclase and plagioclase. The stone displays uniform texture and is susceptible to polishing, but on weathering it dulls over a few years and turns reddish over longer periods. The monzonite is cut by a pronounced joint set striking 130 degrees and dipping steeply east, together with a sheeting, spaced up to 1.2 metres apart that follows the contours of the ridge, dipping gently east on the east flank and west on the west flank. A sample analyzed as follows (CANMET Report 452, page 119, sample 1515):

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PHYSICAL PROPERTIES

Specific gravity 2.882

Pore space (per cent) 1.304

Crushing strength (dry) (lbs/sq.in.) 28,167

Transverse strength (lbs/sq.in.) 1,692

Shearing strength (lbs/sq.in.) 1,053

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The stone was quarried during the early 1900's up to about 1915. The monzonite was used in the base of the Bank of Montreal in Rossland and in the lower storey of the Rossland Post Office.