On what day of the week did the diamond go missing? Three part-time clerks work in the same jewelry store where a large diamond went missing, but the missing diamond was not noticed until the end of the week, after the store manager conducted a weekly inventory It was determined that the diamond could only have gone missing when all three of the part-time clerks went to lunch at noon on the same day. In order to catch the person who took the diamond, you must first determine which day of the week all three part-time clerks went to lunch at noon on the same day. Here are the only clues we have regarding the part-time clerks: 

1. All three clerks go to lunch at noon on only one day of the week. 

2. No clerk gets a lunch break at noon on three consecutive days. 

3. No two clerks get the same day off more than once a week. 

4. The first clerk does not work on Sunday, Tuesday, and Thursday. 

5. The second clerk does not work on Thursday and Saturday. 

6. The third clerk is off on Sunday. Given these six clues, on which day of the week did all three part-time clerks go to lunch at noon on the same day (the day the diamond went missing)?