Celtic Silver Ring and Fish Brooch

These two items were found during the latest visit to the charity shop. The first item being a Celtic Silver ring which is set with some sort of stone that I 'm not too sure what exactly it is, is it a diamond maybe? Bearing in mind under the light actually has a faint blue tint to it, so I'm not sure if it's a diamond or not, but either side of the stone it's got lovely Celtic triangle designs, called a 'triquetra' to be precise and on the other side of the band it's marked 925. Cost of the ring was €25 ($28.10/ £21.63)
I have a sneaking suspicion this is actually a Newbridge Silver piece,- here in Ireland Newbridge Silverware has been designing and crafting tableware and jewellery for over 80 years and this ring is very similar to the pieces they produce at its manufacturing facility in Newbridge, Co. Kildare.
The other piece is the fish brooch which seems to be made of ceramic and roughly painted in red and blue and glazed over, no marks on it at all and cost €0.50 ($0.56/£0.43) Possibly a souvenir.