Eureka
Catherine looked at her surroundings. She was surrounded by utter and total darkness. She grit her teeth and shouted angrily, "I knew it! That king is controlling people with dark magic!"
She suddenly felt cold. She had an intense urge to turn around, and she turned only to see herself staring back at her.
"W- what is this?! That's me! How am I able to see myself?! Is - is this glass!?", she said with astonishment.
Glass and mirrors existed in this world, but they were generally of low quality and people couldn't see their reflections extremely clearly, and they were only available to nobles, merchants and royals as glass was costly. Glass was made naturally by lightning, and while it was not extremely rare, it was still uncommon and was a product in demand.
Mirrors were not available to ordinary commoners and they only heard about it. The people of this world generally used clear water to see their reflections.