Luxullianite - Conce Moor (#202)
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Fact sheet
Description: 

Luxullianite is a rare type of tourmaline-rich granite named after the village of Luxulyan in Cornwall. Luxullianite is formed from boron-rich pegmatitic fluids concentrated during fractional crystallisation of the biotite-rich St Austell granite complex, which formed around 280 million years ago by partial melting of the lower continental crust during the Variscan orogeny. This sample comes from Conce Moor, St Austell, Cornwall.

In thin section the rock contains altered feldspar that appears cloudy and exhibits little visible twinning. Large quartz grains exhibit no alteration. Two generations of tourmaline are present in the sample: the earlier generation is formed of equidimensional patchy brown and blue grains 0.5–1 mm in diameter; the later tourmaline grains are finer grained needles most commonly associated with the quartz and sometimes radiating bundles of tourmaline needles.

In Place
In Time
Location description: 
Conce Moor, St Austell, Cornwall
Accuracy:
Timescale:
Timescale: 
Permian
Ma = Millions of years ago
In Focus
Collection:
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Type:
Type: 
igneous
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Rock-forming minerals:

Rock forming mineral:

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