Antique enamelled silver gold ring with diamond and two rubies

My newest jewelry where I urgently need your help.
This ring is set in silver and decorated with blue and white enamel. Decorated with two rubies and a small diamond on top. The band is made of 14K gold and there are no hallmarks at all.
Because I really want to know how this ring was dated, I naturally started looking. Many rings from the 16th century were made in a similar way. Anyone have an idea how old this ring could be? Please share your views.