Artificially produced citrine tends to have a rich yellowish orange colour and can even be almost brown. Natural citrine has a very subtle yellow or golden colour. Although it can also be distinctively orange, the crystals would never include opaque white quartz.
A natural citrine crystal in this size would command an eye-watering price.
Many minerals are heat treated to enhance or change their colour. This practice has been going on for thousands of years. It's extremely unusual for a fine ruby or sapphire not to have been heated.
The vast majority of citrine geodes are not natural citrine.
Despite having been heated these large and chunky citrine crystals are exceptionally tactile. Like most of the world's heated amethyst they come from Brazil.