Our “dark side” These products are based on antique clay added to a natural mineral ore which causes grey to brown up to give an anthracite marble effect colour to the pots. If you want to keep the optical appearance of the pot for a long time, you need to protect it before use with a suitable water proofing agent available at your local DIY stores. Depending on the processing and combination of clays the colour of basalt products may vary from darker to light as well as from brownish to dark grey which gives each item an individual appearance. You can choose from a wide range of shapes and sizes, from bowls to window boxes and everything in between and add a saucer for indoor use. Efflorences are an important part of these products, they are not a product defect.