紅寶石也就是紅色剛玉，因為其中所含Cr+3造成長波紫外線照射下會呈現紅色螢光。
This listing is for one ‘gem round’, 1 inch in diameter, with 4 bright purple-red Ruby crystals from Pakistan, depending on size. Fluoresces neon red under Long Wave Ultraviolet (regular “black light”)!
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