original: obsidian has been used in cardiac surgery , as well-crafted obsidian blades have a cutting edge many times sharper than high-quality steel surgical scalpels , with the edge of the blade being only about 3 nanometres wide .
simplifications: obsidian has been used in heart surgery , as well-crafted obsidian blades have a cutting edge many times sharper than high-quality steel surgical scalpels , with the edge of the blade being only about 3 nanometres wide . obsidian has been used in performing heart surgery , as well-made obsidian blades are much sharper than high-quality steel surgical scalpels , with the blade edge being only about 3 nanometres wide . obsidian used in cardiac surgery also well crafted blades have edges many times sharper than high-quality steel surgical blades of only 3 nanometres wide . obsidian has been used in heart surgery , as well made obsidian blades have a cutting edge many times sharper than high-quality steel surgical scalpels , with the edge of the blade being only about 3 nanometres wide . obsidian has been used in heart surgery , since its well-made blades have much sharper cutting edges than high-quality steel surgical scalpels , and have a blade edge of only about 3 nanometres wide . obsidian is used in cardiac surgery , as constructed blades are sharper and more precise than even the highest quality steel surgical scalpels . obsidian has been used in cardiac surgery because they are sharper than surgical steel scalpels , and contain a blade about 3 nanometres wide . obsidian has been used in cardiac surgery , as well-crafted obsidian blades have a cutting edge many times sharper than high-quality steel surgical scalpels , with the edge of the blade being only about 3 nanometers wide .