It is an etched HC logo which could be ordered along with the glass service. There must have been a full service (72 pieces at least), all with identical monogram. The uranium glasses were the (optional) white wine glasses, not everybody ordered those, after all white wine could be served in clear glasses too. The stem points at 1900-1920 - but do not take this as gospel. Any producer of tableware would be able to supply these glass services - I doubt if you'll ever find out whodunnit.