Luxullianite
Tourmaline-bearing granite
A distinctive tourmaline-rich granite from Cornwall, prized as an ornamental stone for its pink feldspar set with radiating black tourmaline.
- Mohs hardness
- 6-7
- Color
- Pink to reddish with black tourmaline clusters
- Type
- igneous
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Overview
Luxullianite is a rare and ornamental variety of granite characterized by clusters and radiating sprays of black tourmaline (schorl) set in a matrix of pink orthoclase feldspar, quartz, and additional tourmaline. The striking contrast of dark needles against pink feldspar makes it highly distinctive.
It is named after the village of Luxulyan in Cornwall, England, its classic locality. Luxullianite forms where boron-rich fluids altered an originally normal granite, growing abundant tourmaline.
Though not a gemstone, it is treasured as a decorative and monumental stone, most famously used for the Duke of Wellington's sarcophagus.
Formation & geology
Luxullianite forms during the late stages of granite emplacement and cooling, when hot, boron-rich hydrothermal fluids permeate the solidifying granite. Boron drives the growth of tourmaline (schorl), which replaces earlier minerals and crystallizes as needles, clusters, and radiating sprays within the feldspar-quartz framework.
This boron metasomatism is typical of the tin- and tungsten-bearing granites of southwest England, where the Cornubian batholith of Cornwall and Devon produced such fluid-altered, tourmaline-rich rocks alongside greisen and ore veins.
How to identify it
Luxullianite is easily recognized by black tourmaline forming needle-like crystals, rosettes, and radiating clusters embedded in a pink-to-reddish feldspar-and-quartz granite. The bold black-on-pink pattern is its signature.
Hardness is about 6-7. Distinguish it from ordinary granite by the abundance and radiating habit of black tourmaline, and from tourmalinated quartz by its granitic, multi-mineral matrix (feldspar plus quartz) rather than clear quartz alone. The black tourmaline is harder and more brittle, with rounded triangular cross-sections.
Uses & significance
Luxullianite is valued chiefly as a decorative and ornamental dimension stone. Its most famous use is the sarcophagus of the Duke of Wellington in St Paul's Cathedral, London, and it has been employed in monuments and architectural pieces.
It has no major industrial role, but the surrounding Cornish granites are historically important for tin and tungsten. In metaphysical circles, black tourmaline content is associated with protection and grounding, though this is folklore rather than science.
Frequently asked questions
Where does luxullianite come from?
It is named after and classically found at Luxulyan in Cornwall, England, within the Cornubian granite batholith.
What makes luxullianite special?
Its radiating clusters of black tourmaline set in pink feldspar give a striking ornamental appearance not seen in ordinary granite.
How did the tourmaline form in luxullianite?
Boron-rich hydrothermal fluids altered the granite late in its cooling, growing abundant schorl tourmaline.
What is luxullianite used for?
Mainly as an ornamental stone; most famously it forms the sarcophagus of the Duke of Wellington in St Paul's Cathedral.
Luxullianite guides
In-depth guides for identifying, valuing, and understanding Luxullianite.
