Single server multiple databases - extension

Hi

I have 2 databases running in a single server; and I installed extension 'hstore' to one database and it works fine. When I tried to use the same extension in another database, it gives an error saying 'extension does not exist'; nor it allow to install as it complains about its existence.

Any help ?

db1=# CREATE EXTENSION hstore;
ERROR:  type "hstore" already exists
db1=# DROP EXTENSION hstore;
ERROR:  extension "hstore" does not exist
db1=# create table foo(id hstore);
ERROR:  type "hstore" is only a shell
LINE 1: create table foo(id hstore);
                            ^