Editing Blade (section)

====Non-metals====
{{See also|Blade (archaeology)}}
Prehistorically, and in less technologically advanced cultures even into modern times, tool and weapon blades have been made from wood, bone, and stone.<ref>{{cite journal|last1=Driscoll|first1=Killian|last2=García-Rojas|first2=Maite|title=Their lips are sealed: identifying hard stone, soft stone, and antler hammer direct percussion in Palaeolithic prismatic blade production|journal=Journal of Archaeological Science|date=July 2014|volume=47|pages=134–141|doi=10.1016/j.jas.2014.04.008|url=http://lithicsireland.ie/driscoll_garcia_rojas_2014_identifying_palaeolithic_blade_production_journal_archaeological_science_47.pdf|access-date=19 July 2017}}</ref> Most woods are exceptionally poor at holding edges and bone and stone suffer from brittleness making them suffer from fracture when striking or struck. In modern times stone, in the form of obsidian, is used in some medical scalpels as it is capable of being formed into an exceedingly fine edge. [[Ceramic knife|Ceramic knives]] are non-metallic and non-magnetic. As non-metals do not corrode they remain rust and corrosion free but they suffer from similar faults as stone and bone, being rather brittle and almost entirely inflexible. They are harder than metal knives and so more difficult to sharpen, and some ceramic knives may be as hard or harder than some sharpening stones. For example, [[Sapphire#Synthetic sapphire|synthetic sapphire]] is harder than natural sharpening stones and is as hard as alumina sharpening stones. [[Zirconium dioxide]] is also harder than garnet sharpening stones and is nearly as hard as alumina. Both require diamond stones or silicon carbide stones to sharpen and care has to be taken to avoid chipping the blade. As such ceramic knives are seldom used outside of a kitchen and they are still quite uncommon. Plastic knives are difficult to make sharp and poorly retain an edge. They are largely used as low cost, disposable utensils or as children's utensils or in environments such as air travel where metal blades are prohibited. They are often serrated to compensate for their general lack of sharpness but, as evidenced by the fact they can cut food, they are still capable of inflicting injury. Plastic blades of designs other than disposable cutlery are prohibited or restricted in some jurisdictions as they are undetectable by metal detectors.