Dems House of Diamonds goes back to 1969, and I recall hearing the radio commercials constantly on WIS probably as early as the early 1970s. Of course there is no spelling on the radio, so I always got a kick out of them because, well, Diamonds are sparkly, not dim!. And then there was that whole mental image of a house made out of diamonds.. I guess it helps to be 11 to find all that funny.
I'm kind of surprised to notice that the store was right next to the old Book Dispensary as I went to that store constantly, and have no memory of Dems being there. I guess my eyes kind of slid right over anything jewelry related.
In 2004, Dems moved to 1068 Lake Murray Boulevard, where they are still open as Dems Fine Jewelers.
UPDATE 30 September 2011 -- Commenter Andrew sends this picture of the new Dems location on Lake Murray Boulevard: