I am trying to query for all posts with a post format of 'quote.' I have added the post formats to my functions.php with

    add_theme_support( 'post-formats', array( 'image', 'video', 'gallery', 'quote' ) );

I have selected 'quote' as the format for the post in the admin. The last example under [Taxonomy_Parameters][1] shows how to display posts that have the 'quote' format but when I run it in my theme no posts are returned. Here is the code:

    $args = array(
      'tax_query' => array(
    	array(
    	  'taxonomy' => 'post-format',
    	  'field' => 'slug',
    	  'terms' => 'post-format-quote'
    	)
      )
    );
    query_posts( $args );

When I just query all posts and place 

    echo get_post_format();

in the loop it returns the word 'quote' on the front-end. Also, when I var_dump() the query I do not see anything in the array about post format. 

Does anyone know if it is possible to query by post format? If so how?

EDIT - See 5 comment under Bainternet's answer:
This is the code found on index.php of the twentyten theme of a fresh install trying to return format type quotes. I return 'no' instead of 'quote'. Can you see anything that I should change.

    get_header(); ?>
    <div id="container">
      <div id="content" role="main">
        <?php $args = array(
          'tax_query' => array(
    	    array(
              'taxonomy' => 'post-format',
              'field' => 'slug',
              'terms' => array('quote')
            )
          )
        );
        query_posts( $args );
        if ( have_posts() ) : while ( have_posts() ) : the_post();
          echo get_post_format();
        endwhile; else:
          echo 'no';
        endif;
        wp_reset_query();      
        ?>
      </div><!-- #content -->
    </div><!-- #container -->
    <?php get_sidebar(); ?>
    <?php get_footer(); ?>

EDIT 2 - It appears that the WordPress Codex has now changed and the portion on Taxonomy Parameters is only found in Google cache. 

EDIT 3 - FINAL WORKING CODE

    $args = array(
      'tax_query' => array(
    	array(
    	  'taxonomy' => 'post_format',
    	  'field' => 'slug',
    	  'terms' => 'post-format-quote'
    	)
      )
    );
    query_posts( $args );

The twenty-ten edit form the first edit will be...

    get_header(); ?>
    <div id="container">
      <div id="content" role="main">
        <?php $args = array(
    	  'tax_query' => array(
    	    array(
    	      'taxonomy' => 'post_format',
    	      'field'    => 'slug',
    	      'terms'    => 'post-format-quote'
    	    )
    	  )
    	);
        query_posts( $args );
        if ( have_posts() ) : while ( have_posts() ) : the_post();
          the_title();
          echo get_post_format();
          echo '<br />';
        endwhile; else:
          echo 'no';
        endif;
        wp_reset_query();      
        ?>
      </div><!-- #content -->
    </div><!-- #container -->
    <?php get_sidebar(); ?>
    <?php get_footer(); ?>

  [1]: http://codex.wordpress.org/Function_Reference/query_posts#Taxonomy_Parameters