What type of Blue Butterfly?

What type of Blue Butterfly?

Observation - What type of Blue Butterfly? - Global. Description: Blue butterfly seen in Suffolk about 30-35mm wingspan. I had hoped would be Star Studded but no typical brown outer ring on upperside wings. Can't easily identify. It's not a common blue is it??

Blue butterfly seen in Suffolk about 30-35mm wingspan. I had hoped would be "Star Studded" but no typical brown outer ring on upperside wings. Can't easily identify. It's not a common blue is it??