Editing Obsidian (section)

==Current use==
Obsidian can be used to make extremely sharp knives, and obsidian blades are a type of [[glass knife]] made using naturally occurring obsidian instead of manufactured glass. Obsidian is used by some surgeons for [[scalpel]] blades, although this is not approved by the [[US Food and Drug Administration]] (FDA) for use on humans.<ref>{{Cite web|last=Shadbolt|first=Peter|date=April 2, 2015|title=CNN Health: How Stone Age blades are still cutting it in modern surgery|url=https://www.cnn.com/2015/04/02/health/surgery-scalpels-obsidian/index.html|access-date=September 7, 2023|publisher=CNN|language=en}}</ref> Well-crafted obsidian blades, like any glass knife, can have a cutting edge many times sharper than high-quality steel surgical scalpels: the cutting edge of the blade is only about three nanometers thick.<ref name=obsidian1>{{cite journal|last=Buck|first=BA|date=March 1982|title=Ancient Technology in Contemporary Surgery|journal=The Western Journal of Medicine|volume=136|issue=3|pages=265–269|pmid=7046256|pmc=1273673}}</ref> All metal knives have a jagged, irregular blade when viewed under a strong enough [[microscope]]; however, obsidian blades are still smooth, even when examined under an [[scanning electron microscope|electron microscope]].<ref name="Haviland">{{cite book|last=Haviland|first=W.A.|author2=Prins H.E.L.|author3=Walrath D.|author4=McBride B.|title=Anthropology: The Human Challenge|publisher=Cengage Learning|year=2010|edition=13|pages=196|isbn=9780495810841|url=https://books.google.com/books?id=Fm2RY5ZKmDIC&q=%22payson+sheets%22+obsidian+blade&pg=PA196|access-date=September 27, 2012}}</ref> One study found that obsidian incisions produced fewer [[inflammatory cell]]s and less [[granulation tissue]] in a group of rats after seven days but the differences disappeared after twenty-one days.<ref>{{cite journal|last1=Disa|first1=J. J.|last2=Vossoughi|first2=J.|last3=Goldberg|first3=N. H.|title=A comparison of obsidian and surgical steel scalpel wound healing in rats.|journal=Plastic and Reconstructive Surgery|date=October 1993|volume=92|issue=5|pages=884–887|doi=10.1097/00006534-199392050-00015|pmid=8415970}}</ref> [[Don Crabtree]] has produced surgical obsidian blades and written articles on the subject.<ref name="obsidian1" /> Obsidian scalpels may be purchased for surgical use on [[Animal testing|research animals]].<ref name="FST Obsidian Scalpels">{{cite web|last=Fine Science Tools (FST)|title=FST product catalog|url=http://www.finescience.com/Special-Pages/Products.aspx?ProductId=296&CategoryId=56|publisher=FST|access-date=September 7, 2012}}</ref>

The major disadvantage of obsidian blades is their brittleness compared to those made of metal,<ref>Fine Science Tools – "[https://www.finescience.com/en-US/Products/Scalpels-Blades/Micro-Knives/Obsidian-Scalpels Obsidian Scalpels]" </ref> thus limiting the surgical applications for obsidian blades to a variety of specialized uses where this is not a concern.<ref name = "obsidian1" />

[[File:Pig.snowobsidian.jpg|thumb|right|Pig carved in snowflake obsidian, 10 centimeters (4 in) long. The markings are [[spherulite]]s.]]
Obsidian is also used for ornamental purposes and as a [[gemstone]].<ref>{{Cite book|url=https://books.google.com/books?id=2UX1CAAAQBAJ&q=%C2%A0Obsidian+is+also+used+for+ornamental+purposes+and+as+a+gemstone.&pg=PA502|title=Dictionary of Gems and Gemology|last=Manutchehr-Danai|first=Mohsen|date=March 9, 2013|publisher=Springer Science & Business Media|isbn=9783662042885|language=en}}</ref> It presents a different appearance depending on how it is cut: in one direction it is jet black, while in another it is glistening gray. "[[Apache tears]]" are small rounded obsidian nuggets often embedded within a grayish-white perlite [[Matrix (geology)|matrix]].

[[Pedestal|Plinths]] for [[phonograph|audio turntables]] have been made of obsidian since the 1970s, such as the grayish-black SH-10B3 plinth by [[Technics (brand)|Technics]].