I cannot see the "embed in webpage" option

I cannot see the "embed in webpage" option

I uploaded an .xls document and I cannot see the "embed in webpage" option in the toolbar but I do see this option in other documents (also .xls) that I uploaded.  The documents that show the option do not have the .xls extension when shown in My Folders. The Icon for this document also looks different from the others as does not have a "pencil" diagonally across the spreadsheet icon. What am I doing wrong with this document?