International Rock Day
"Geologists have a saying - rocks remember."
~ Neil Armstrong (1930-2012)
Are you a "rockhound" (an amateur geologist)? Do you have a rock collection? If so, you are in good company. Notable rockhounds include art critic and essayist John Ruskin (1819 -1900), James Smithson (1765-1829), benefactor of the Smithsonian Institution, and writer, poet, and statesman Johann Wolfgang von Goethe (1748-1832). One stone prized, quarried, and used since antiquity is granite (named for its grained appearance). The Highlands and Islands of Scotland share a unique geological ancestry including ancient granite intrusions, estimated to be approximately 585 million years of age and provide a rich area of study for many, including James Hutton, the "father of modern geology." Scottish granite travels the world through the sport of Curling as most curling stones are traditionally fashioned from Blue Hone and Ailsa Craig Common Green granite taken from the Ailsa Craig. Additionally, masons and migrant granite workers from Aberdeen, "The Granite City," (named for the many buildings constructed in the mid-18th through the mid-20th century which incorporated locally quarried grey/silver granite into its many buildings) brought their skills to other parts of the world, including the eastern seaboard of the US and New South Wales, Australia. Rock on!
The scientific study of rocks is called petrology, which is an essential component of geology. Today is the day to examine or start your own rock collection, be they the more common ones that make up the landscape, or the rarer ones classified as gems.
Granite is an igneous hard, coarse-grained rock making up most of the earth. It consists chiefly of three minerals: quartz, alkali feldspar (which contain alumina and silica) and plagioclase feldspar. It also contains small amounts of other minerals such as hornblende and biotite mica.
Granite and related marble industries are considered one of the oldest industries in the world, existing as far back as Ancient Egypt. Aberdeen, which is constructed principally from local granite, is known as "The Granite City".
Granite is also one of the rocks most prized by climbers, for its steepness, soundness, crack systems, and friction. Curling stones are traditionally fashioned of Ailsa Craig granite.
The colours in this tartan reflect the imposing scenery when journeying north from Perth to Inverness or through to Royal Deeside, granite being the predominant composition of the surrounding unique hills and mountains. The age of the granite from the Scottish Highlands is estimated to be approximately 585 million years of age.
If you are fascinated by rocks, you may enjoy a special facebook page, The Amazing Geologist. To visit this page, click the granite exposure photograph taken at Lochnagar, in the Grampians of Scotland, about five miles south of the River Dee near Balmoral.