Dumortierite in 4 mm reportedly supports its wearer's ability to communicate and express themselves. It reportedly makes it easier to express yourself clearly and confidently, as well as to express your thoughts and feelings. It has a blue-grey colour, though its shade can vary from light blue to dark blue. It is said to have mainly harmonising effects on its wearer. People also seek it out because it reportedly supports clear thinking and removes negative thoughts and limiting patterns of behaviour. It is also often associated with opening the third eye. Each bead is unique, so it may vary by approximately 0.5 mm. Read more about dumortierite in our article about dumortierite.