Can someone id this please?

1.) This thing is colored white and sort of look like a cracked glass..
2.) I don't know what type of coral this is..

 

hard to tell with the first two photos, but the third is a birds nest acropora

 

Thanks zissou. I searched in google for the first id and i think its a sponge. Do you know the care for the birds nest? Food, lighting, water flow, etc. I have it middle level in my tank..

 

It's a stony coral so high lighting and medium to strong flow soots them.