Misc: In 1955 Willem---------- , actor, born. ?

Questions

After how many years of marriage is an emerald wedding anniversary celebrated?

Which jeweller established the term sterling as the standard for silver in the United States in 1851?

On which scale is the hardness of minerals measured?

What is the name given to the way in which stones such as diamonds are cut so as to have facets which reflect the light in different directions?

What did a pouncet usually contain?