Marc Gaudin is on record as the first chemist to create lab created gemstones. The French chemist achieved this feat in 1837, even if the gemstones lost transparency after cooling. It will take another four decades for any meaningful advance in the synthesis of gemstones. Edmond Frémy discovered the now-popular flame fusion method to create solid gemstones from a mix of lead oxide ... https://www.gemsngems.com/product-category/lab-created/hydrothermal-pulled-czochralski-gemstones/hydrothermal-emerald/