Gabbro /ˈɡæbroʊ/ refers to a large group of dark, coarse-grained, intrusive mafic igneous rocks chemically equivalent to basalt. The rocks are plutonic, formed when molten magma is trapped beneath the Earth’s surface and cools into a crystalline mass.
The vast majority of the Earth’s surface is underlain by gabbro within the oceanic crust, produced by basalt magmatism at mid-ocean ridges.
Gabbro was named by the German geologist Christian Leopold von Buch after a town in the Italian Tuscany region. Essexite is named after the type locality in Essex County, Massachusetts, U.S.A.
Gabbro-diabase is used to produce a block of stone road ( paving blocks, mosaic block , curbs ) , for the production of ritual items , in the precision engineering, as well as in the construction of a ground stone, part goes to bottles ischeben used as a stone for stoves and heaters in the baths saunas.
Blocks of gabbro-diabase and its products in all respects comply with the requirements of GOST 9479-98 » blocks of rock to produce tiles , architectural , memorial and other products .»
Total world production area there are three block gabbro-diabase :
Australian gabbro- diabase. On the quality of the Karelian identical , but more expensive.
Ukrainian gabbro- diabase. On the quality is much inferior to Karelian , but cheaper in the Medium twice. Contains a large amount of iron impurities , which impairs the quality of products , drawing, printed on the stone quickly fades .
Karelian gabbro- diabase. It has a perfect black , high decorative properties , characterized by a low degree of abrasion resistance, frost resistance , durability , long retains inflicted on him drawing .
Physical and mechanical properties of gabbro- diabase Karelia
Density — 3.07 g/cm3
Mark on the compressive strength — 1400 kg/cm2
Water absorption — 0.1 %
Frost resistance — 300 cycles
Attritive — 0.07 g/cm2 I1
Radioactivity — to 74 becquerels / kg
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