Simplify the following text for a Grade 9 native English-speaking person.
Original: Even the sharpest metal knife has a jagged , irregular blade when viewed under a strong enough microscope ; when examined even under an electron microscope an obsidian blade is still smooth and even .
Simplified: Even the sharpest metal knife has a jagged , irregular blade when viewed under a strong enough microscope . When examined under an electron microscope an obsidian blade is still smooth and even .