These are available in several colours: #white, #milky_white, #yellow, #green, #black, #red, #grey, liver colour and many others. The best are the liver colour from #Yemen, which are #difficult to #obtain and expensive. It has #great #religious significance and for a #Shia it is a must.

A #Hadith from #Janabe_Salman_Farsi r.a. states that "the last #Prophet requested #Imam #Ali to wear a #ring on the right so that he may be listed among the #Muqarrabeen (those near to Allah). The #Imam asked the #Prophet as to who the #Muqarrabeen were, to which the Prophet replied #Janabe_Jibreel and #Janabe_Mikaiel. Then the #Imam inquired as to which #stone should he wear. The #Prophet replied #Aqeeq (cornelian), as this #red #stone had accepted the #Oneness of #Allah, the #Prophethood of the last #Prophet, and the #vicegerency of #Ali #ibne #Abi #Talib, and the heavens for #Ali's friends and #Shias".