Lab grown gems
Gems made in labs can contain a mix of citrine and amethyst crystals, glass with coloring or refraction elements with many other variants. Most lab-created gemstones are usually a copy of existing crystals with very few exceptions.
Lab-made gems are usually cheaper, easier to produce, and can be available in different colors. In some cases, lab-created gemstones might have superior features compared to their natural variants.
The hydrothermal process requires an intense amount of heat and pressure to form crystals from elements. A set of compatible, stable elements placed under high heat causes a reaction, forming crystals with different features.