Mineral Family: Dolerite, Igneous Rock Major Elements/Minerals: Augite, Calcium, Feldspar Minor Minerals/Rocks: Chalk, Snow Quartz
Color: Green and black, molted white Gravity: 3-3.05 Hardness: 7 Luminescence: Unknown Texture: Course-grained Transparency: Opaque
Where is Presli Bluestone found?
The only deposit of Preseli Bluestone is Preseli Hills in Western Wales.
What is Preseli Bluestone?
Preseli Bluestone is not a single mineral, but rather a rock. As an easy way to understand the difference, think of rocks as being like cookies and minerals as being the ingredients which make up those cookies. Many different minerals are used to create a rock! In the case of Preseli Bluestone, the rock is a rare variety of Dolerate (more commonly called Diabase in North America). The main chemical element is Calcium and the major minerals are Feldspar (green) and Augite (black). Many stones are also flecked with white chalk or Snow Quartz.
How is Preseli Bluestone formed?
Preseli Bluestone is a metamorphosed Dolerite, created by low grade regional metamorphism. The original Dolerite rock was of igneous origin and formed at medium to shallow depths within the Earth’s crust.
The original Preseli Bluestone came from Carn Meyne, a rocky outcropping in the Preseli Hills of Western Wells. Today, Carn Meyne is protected from both commercial mining and amateur rockhounds, so it is illegal to remove any stones from Carn Meyne or the immediate surrounding area. Some of the Preseli on the market comes from private sources of stones that were taken from the mountain before any laws were put in place. Recently, a small business near Preseli Hills has secured exclusive rights for quarrying. The stones do not come from Carn Meyne, but rather a nearby location and are geologically identical.
Preseli Bluestone enhancements
Green Dolerite from other locations have on occasion been sold as “Presli Bluestone”. True Preseli Bluestone comes from Wales and will contain white spots, although depending on the size of the stone, spots may or may not be present! Always buy from a reputable seller. Preseli Bluestone are fully natural, and not enhanced in any way besides cutting, tumbling and polishing.
Julie Abouzelof is the owner of Moonrise Crystals and an advocate for responsibly sourced gems and minerals. Her first career was in education teaching history, geology and anthropology, as well as working with special-needs students. She is now a heart-centered entrepreneur who encourages mindfulness and positive action to heal ourselves and the world. Julie lives in Hawaii with her lover and a little parrot named Darwin.