Jewlery Rule/Ejection

[blacktiger]

In the top of the 1st yesterday in a Junior Varsity game, the second hitter came to the plate with a necklace on. The homeplate umpire proceeds to eject him from the game without warning. I was upset as the home team coach because I thought the umpire should have used some judgement here. I was prepared to tell him that when after the inning he asks me if I minded if the player reentered later in the game. I was glad that he had changed his mind.
My question is: What is the exact rule for jewlery? Is it an automatic ejection? Earlier in the year I saw a varsity game worked by association members who do thing by the book and they gave a team warning in a similar situation. Somebody help me here. I am a coach who doesn't know all of the rules. I hate to say that as a basketball official but it is true.