Answered by Shaykh Muhammad ibn Adam al-Kawthari
Platinum rings
In the name of Allah, Most Compassionate, Most Merciful,
For men, only silver rings are permissible. Women have been given the permission to wear gold and silver rings without doubt. However, rings made form other metals are not permissible. Also, it seems that rings made from other plastic substances will not be permissible for women, thus should be avoided.
However, if these rings were plated with gold or silver, then it would be permissible.
This has been explained in detail in a earlier post. See below:
And Allah knows best
Muhammad ibn Adam al-Kawthari
Darul Iftaa, Leicester, UK