Second Hand Jewellery Box on Instagram: "Your gemology lesson of the day- how to quickly identify if something is rock crystal or glass 🔬 💎 It’s hard to fully explain the gemology in these short clips but effectively when light enters a natural crystal it follows the crystal structure of that gemstone, which can split the light in two. When we use polarising filters this helps us ‘sort out’ these light rays and see where they intersect. We can then unscramble these light rays with a small cyli

Blue Gemstones: 37 Varieties, Properties & Care Guide - IGS