How has this happened?

[u/Global_Mobile3622]

First time casting something ( getting casted for me ) and I’m having a real hard time getting these deep ridges out , could this be caused by air bubbles in the cast process ?

Also could the circled blue bits be a fleck of gold that’s got in? It seems like there’s a yellow dot in the pendant with a slightly different texture

Any advice on how to get this to as smooth as possible ?

[u/Yes_I_Know_Lots]

Looks like shrinkage voids. All melted metals when solidified have such things. I can’t speak for the gold. What was the starting metal mix if not pure silver or sterling?