Whilst we were on our travels, we came over an ellegurra.  I think it is a custom from Mexico.  It is meant to protect you against you about negative energy coming into the home.

You get a favourite stone, pebble or crystal, that you like then wrap it in air drying clay, and decorate with shells and glitter ( and pencil sharpening as my daughter wanted to!!) then leave by your front door to keep on guard.