First, take precipitation and crystallisation. This is not as straightforward as it might at first appear. Tung, Paul, Midler, and McCauley indicate that the process of reactive crystallisation is also known as precipitation but then go on to say that the term reactive crystallisation is generally applied only when the product is crystalline. If the product is amorphous or a mixture of amorphous and crystalline forms, then the term precipitation applies. Davey and Garside, on the other hand, discuss particle size, commenting that crystals can be almost any size from a few nanometres to several millimetres; traditionally, when crystals are less than a few micrometres in size, the term precipitation is used. For most of us, I suspect that we think in terms of the speed with which a solid was formed and deposited from solution, with precipitation usually being ‘fast’ but what is fast, and so it goes on.
I ask that chemists and engineers aim to be more precise in the terms applied and suggest that, unless it is obvious or the process is known to provide crystalline product, then the term precipitation is universally adopted for a reactive crystallisation such as salt formations that result in essentially immediate depositions of solids, and for all other cases simply state that solid was deposited, harvested, etc. Adopting this simple distinction can avoid the forward progression of what may have been a ‘throw-away’ comment in a laboratory book about the ‘isolation of crystalline solid’ into a legal battle in 15 years’ time over solid state and patent validity!
So what about an amorphous solid versus a crystalline solid? Much as above, unless you know the solid product to be crystalline either by analysis or by virtue of the known process of isolation, avoid using either term simply state ‘solid product’ was isolated etc. From a patent viewpoint, only factual data should be recorded; unless there is analytical data to confirm crystallinity, this is conjecture only, albeit educated conjecture.I suspect that people like to use the terms "crystals" and "crystallize" rather than "solid" and "deposited" because it sounds more scientific. I certainly do not haul out the microscope to look at every solid product that I make (maybe I should?)
Well, time for me to go harvest some solid...