This quartz monzonite comes from Ronez Quarry - the largest quarry on the island of Jersey, in the Channel Islands. The quarry supplies aggregates for local construction and road building and has been active since 1651. While it is locally known as granite, the rock is in fact a quartz monzonite since it has roughly equal amounts of plagioclase and orthoclase feldspar, but lower quantities of quartz than a true granite.
The thin section exhibits large altered plagioclase and orthoclase grains, often with many inclusions. Small biotite mica and pale green amphibole grains are common, although both are partially altered to chlorite.
The United Kingdom Virtual Microscope (UKVM) collection consists of igneous, sedimentary and metamorphic rocks from around the UK.
It is intended as a teaching resource, helping to tell the story of the common rock types and how they form, and reflecting the history of the UK at the margins of the continent of Europe. The collection is a series of teaching sets, for example igneous rocks from the North Atlantic Igneous Province and SW England; high-temperature metamorphic rocks from Scotland and low-temperature metamorphic rocks from Wales; and sedimentary rocks, including English limestones and sandstones.