The US Patent and Trademark Office (USPTO) has concluded that recent decisions of the US Supreme Court relating to patents for genes and for diagnostic methods mean that mixtures of ‘naturally-occurring materials’ are not patent-eligible – at least, not unless one or more of the components has been ‘changed’ in some way from its natural state.
The USPTO has published an extensive (93-slide) presentation used for examiner training [PDF, 972KB] on the Supreme Court’s interpretation of section 101 of the US patent statute in Mayo Collaborative Services v Prometheus Laboratories, Inc. (2012) and Ass’n for Molecular Pathology v Myriad Genetics, Inc. (2013). In an example to be found on slide no. 55, examiners are told that ‘gunpowder’ would not be eligible for patenting (even if it was not already known) because as ‘a mixture of three naturally occurring materials: potassium nitrate, sulfur and charcoal’ it is ‘not markedly different’ from naturally-occurring materials, ‘because none of the components have been changed.’
This will no doubt come as a surprise to many people, who would not have held any real doubts that gunpowder was ‘invented’ by the Chinese, around the 9th century C.E. Indeed, as the quite well-researched Wikipedia entry on the History of Gunpowder explains, it took a few centuries, and a number of educational accidents, to refine the proportions of gunpowder’s constituent parts to produce maximum explosive effect.
While there is no question that effective gunpowder can be made by combining materials that occur in nature, the resulting combination is not (fortunately) naturally-occurring! There is, to my knowledge at least, nowhere in the natural world at which dangerously flammable reserves of potassium nitrate, sulphur and charcoal can be found just lying around in wait of a serendipitous lightning strike! (Interestingly, however, there is evidence that 17 nuclear fission reactors once formed and operated naturally for around a million years in what is now Gabon, western Africa.)
Conventional wisdom would have it that, in the case of a combination like gunpowder, the prospective invention lies in bringing the components together to create something useful. If the combination is not previously known, and not obvious, then it should be patentable. Apparently, the USPTO no longer believes in this conventional wisdom!