How to Tell the Difference Between Onyx and Obsidian Stones
Learn how to identify onyx and obsidian by appearance, hardness, and fracture for accurate stone identification.
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To tell if a stone is onyx or obsidian, observe its appearance and test its hardness. Onyx is banded and can be various colors, including black, while obsidian is usually black and has a glassy luster. Obsidian is harder and sharper (5.5 on the Mohs scale) compared to onyx. Finally, obsidian will have sharper edges when broken due to its conchoidal fracture, whereas onyx will show a smoother break. Using these characteristics, you can distinguish between the two stones effectively.
FAQs & Answers
- What are the main visual differences between onyx and obsidian? Onyx is typically banded with multiple colors including black, while obsidian is usually solid black with a glassy, shiny appearance.
- How does the hardness of onyx compare to obsidian? Obsidian rates around 5.5 on the Mohs hardness scale and is harder than onyx, which is generally softer.
- What type of fracture does obsidian have compared to onyx? Obsidian breaks with a conchoidal fracture producing sharp edges, whereas onyx typically has a smoother break.
- Can color alone be used to identify onyx versus obsidian? No, because onyx can come in various colors and obsidian is usually black; other factors like hardness and fracture should be considered.