Dear researchers I need your help because I'm lost,

I've ordered some copper phosporus alloy (CuP with 15% of Phosphorus) and during the summer a blue loose solid crystalised on the surface I was wondering what it could be?

apparently it could have been an oxidation since a lot of humidity was in the air during this summer but I can't find what compound it could have formed upon oxidation?

I thought also about contamination of sulfur with formation of a sulfate salt but it seems far fetched do you have other ideas?

thank you for the help

zakaria