Cincin Batu Aqiq (agate)
Learned writer of "Al Majalis al Hatimiyyah", 3rd Al Dai al Fatemi, Syedna Hatim Mohiyuddin (Hutaib, Yemen) inquired: 
"Did anyone know that Adam (A.S.) also used to wear a ring of Cornelian the colour of which was red"?
Rasulullah (S), his Ahl al Bait and Ash'ab have also worn Gems. In many instances, Jibrael presented Gems in honour of Rasulullah (S). Once Jibrael came in the presence of Rasulullah (S), and presented him a ring of red Cornelian and asked him to wear it, and to advise its benefits to his Ummah.  Since then wearing a ring of Cornelian is Sunnah. A Hadith says: 
"Wear the Aqiq and remove the poverty".
As per tradition, red Aqia is attributed to Rasulullah(S), yellow attributed to Syedah Fatimah and white to Amir al Muminin. Abi Jafar Imam Mohammad al Baqir says: 
"if a person possesses a ring set in Aqiq and turns it towards his palm and then looks at it, and recites Surah al Qadar 97, then Allah keeps him protected the whole day, from all troubles, wherever they are descended, from heaven or earth and, he will be protected until the evening by Allah, and Awliya(saints) will guide him".
Famous Greek philosopher, Aflatun wrote that white Aqiq helps in increasing memory, yellow Aqiq assists in solving problems and red Aqiq promotes dignity.  Anbiya Bani Israel used to wear this Gem with pleasure. It is a unique Gem, which has several kinds of values. From centuries people of different schools of thoughts have used it with great reverence. Colour of Aqiq Yamani in daylight is orange-brownish and it has got longitudinal stripes which maybe light yellow or dark brown, depending on the strength of the stone. Jews, Christians and Muslims unanimously agree on the spiritual, Medicinal and super natural values and importance of this Gem. It is known in English as Agate also.
Learned writer of "Marifat al Jawahir", Syedi Ibrahim Saify has discussed following benefits: 
Its regular use controls the habit of anger & calms the temper
Rasulullah (S) has declared its use in ring as Barakah 
Victory over opponents & helps in negative atmosphere
Protection from difficulties, trials & helps to lessen sorrow
Relaxation from labour pain quickly
When one wears it, his enemy feels fear
It is helpful to fulfill ones desire & helpful to remove poverty
It protects from chest pain, helpful for heart & in digestion
It also provides protection from the poison of insects
As a booster of charm & improve sense of humor
A luck bringer when traveling
It strengthens concentration
Helpful in healing of kidney, bladder & liver problems
Helps in career success
Helps finding strength from within
Helps in focusing to realizing goals & decision making
Helps cure blood diseases & heal wounds
Helps increase energy, helpful in infertility & impotency