A phanerite is an igneous rock with a microstructure that is made up of crystals large enough to be distinguished with the unaided human eye. (In contrast, the crystals in an aphanitic rock are too small to be seen with the naked eye). Phaneritic texture forms when magma deep underground in the plutonicenvironment cools slowly, giving the crystals time to grow.
Granite is a type of felsic intrusive igneous rock that is granular and phaneritic in texture. Granites can be predominantly white, pink, or grey in colour, depending on their mineralogy. Strictly speaking, granite is an igneous rock with between 20% and 60% quartz by volume, and at least 35% of the total feldspar consisting of alkali feldspar, although commonly the term "granite" is used to refer to a wider range of coarse grained igneous rocks containing quartz and feldspar.
Some examples of polished granite
At the listed co-ordinates you will find a Fishermans Memorial, which is made of granite.
I think of it as the Fisherman’s Phanerite.
Please observe the rocks colour, grain size, texture and any tool marks on it in order to answer the following questions from your observations.
1. Which of the example of granite in the picture on this cache page does the rock that the Fisherman’s Memorial is made of most closely resemble?
2. Describe the size of the three main crystals that are visible in the Granite that the monument is made of?
3. Do you think that the rock cooled rapidly or cooled slowly? And why do you think this?
4. The large stone that is closest to the three white signs that describe the various local fishing industries shows clear evidence of the method used to harvest the granite. Looking at the rock, how do you think it was harvested?
5. Walk towards the edge of the water. The rocks that protect and make up the breakwater also appear to be a type of granite but are a very different colour than the monument. Which of the example of granite in the picture on this cache page does the rock that the breakwater is made of most closely resemble?
6. Describe any other differences that you observe when comparing the two different types of rock.
Please send your answers to the cache owner using the messenger feature in geocaching.com.
You may log you visit as soon as your answers are submitted. The cache owner will respond confirming your approval to log the cache or asking for additional information if there are concerns about your answer.
Acknowledgements – Wikipedia.