"You destroyed Metallia with the Silver Imperium Crystal?" asked Luna. "That's amazing Usagi. Queen Serenity always said that you had great potential, but even she couldn't manage to do that."
Usagi looked embarassed. "I'm sure that she could have, really."
"No," Luna insisted. "She really couldn't. That's why she had to seal the Negaverse away: no matter what she did to Beryl, she couldn't directly affect Metallia. How did you do it."
"Uh..." Usagi hesitated and then laughed nervously. "I'm not really sure..."
Luna sighed. Same old Usagi.
"The crystal looks awfully fragile. Is it okay for me to carry it about everywhere? You know how clumsy I can be sometimes."
"That's a very responsible question, Usagi, but you don't need to worry. The Silver Imperium Crystal is almost indestructable."
"So it wouldn't matter if someone, say, put it in their sock and then smacked someone else over the head with. Two or three times."
"USAGI! That's the Silver Imperium Crystal! You can't do that."
Usagi winced, "I'm just saying, Luna. You know what my brother's like."
"Oh." Luna frowned. "Well it wouldn't damage the crystal, but someone could be seriously hurt if they were hit like that. Please don't let your brother do that."
Luna watched Usagi suspiciously for the next few days and then forgot about it. She never did work out how Usagi defeated Metallia with the Silver Imperium Crystal, even after Usagi used it to defeat Wiseman and Pharaoh 90.
Usagi was just glad that none of the other scouts had been around to see her clouting bad guys on the head with the Silver Imperium Crystal inside her sock. Luna would never have shut up about it.