Basalt Clay is based on an antique clay added to a natural mineral ore which causes the grey to brown up to give an anthracite marble effect colour. Depending on the combination of clay’s the colour of Basalt products may vary from darker to light as well as brownish from dark grey which gives each item an individual appearance. Efflorescence are an important part of these products, they are not a product defect. Cylinder and Lip pots are a stunning addition to your patio and are amazing styled together in different sizes.