Rosewater is a product of the distillation of rose petals. The raw distillate of rose petals is really a layer of oil known as rose attar that is typically used in perfumes floating on top of a water layer, which is the actual rosewater. Muslim chemists first commercialized rosewater production during their Golden Age, mainly for beverages and perfumes. Rosewater is also quite common in Persian and Indian cuisine.
To make rosewater, take a large pot, place a brick in the bottom of it, and place a smaller bowl on top of the brick. Add enough fresh, organic rose petals (most roses from flower shops are not appropriate) to reach the top of the brick, then add water just to cover. Place the lid on the pot upside down. Bring the pot to a simmer, reduce the heat to barely hold it there, and then add ice to the inverted lid. Water vapor containing rose essence will condense on the colder lid and drip into the smaller bowl. Check the rosewater from time to time, and stop the process when the liquid has a strong rose aroma and flavor. This rosewater can be preserved with a bit of vodka.