This is my vintage large Abalone shell from California.  This unique Abalone shell arrangement has various other sea shells including coral nestled and wired into the base.  We bought this in California more than 50 years ago.  The Abalone shell is about 7" high and 9" in length.  This oval arrangement measures about 10X7.  The palm tree is plastic.  I am not sure what the base is made of.  This weighs almost 4 lbs.  Great decor for any room, very unique.