Basalt Clay is based on an antique clay added to a natural mineral ore which causes grey to brown up to give an anthracite marble effect colour. Depending on the combination of clay’s the color 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. Saucers are a stunning addition to your pots visually, but also help to keep your plant roots hydrated in summer weather.