£1.25 – £3.35
Graphic granite is an igneous pegmatite rock from Iveland, Norway, which forms in intrusive batholithic bodies that have a felsic composition. As such, the rock is mainly composed of quartz and orthoclase feldspar crystals and lacks any mica, making the rock leucocratic. These samples have what is known as a graphic texture, due to the formation of the crystals, which result in an appearance similar to that of cuneiform text which was once used by ancient human cultures. A brightly coloured, eye catching rock, the samples are suitable for collectors and educational use at higher levels and come available in three sizes. Each specimens is supplied in a card tray with an information label.
Graphic granite is an intrusive igneous rock with felsic minerals expected of granites such as quartz and feldspar crystals and are very rich in these minerals to the point that the rock hardly exhibits any (or in some case none) mica minerals at all. Due to this, graphic granite can further be sub-divided and known as a leucocratic rock, which are rocks which exhibit a very low contents of ferromagnesian minerals, in this case, biotite mica. Due to this, the rock is actually not a true granite, but a pegmatite, but is often referred to as such for ease. The name of the rock is derived from the Latin word, 'graphic' which means 'to write', a nod towards the unique texture of the rock which from certain angles can appear like text on the stone, similar in appearance to ancient texts used on stone tablets by past cultures and is known as cuneiform writing. This texture has formed due to the absence of mica minerals, resulting in the quartz and feldspars to inter-grow with one another completely. As a pegmatite, this rock would have formed as a large batholith intrusion within a high temperature environment at depth, which would have resulted in the magma cooling slowly, leading to large size crystals, over 2 cm in size being formed. These particular samples come from Iceland in Norway and are ideal for young to mature collectors of varying levels due to their unique appearance, they are also suitable for higher level education to describe that not all granites or pegmatites will look like one will expect on the face. Specimens are available in three sizes and come supplied with a card tray and label.