Opal look-alikes
Hydrated amorphous silicon dioxide (SiO2·nH2O)
Got a photo? Identify rocks instantly with the Rockby app
Open the appSeveral rocks and minerals can be confused with Opal. Below are documented look-alikes and the features that tell them apart. Never rely on a single feature. Always check multiple properties.
Similar rocks to compare
Chalcedony
Cryptocrystalline quartz (SiO2)
Also known as: Agate, Jasper, Carnelian, Onyx
Quartz
Silicon dioxide (SiO2)
Also known as: Amethyst, Citrine, Rose Quartz, Smoky Quartz
Glass
Amorphous silicon dioxide (SiO2) with various modifiers
Also known as: Obsidian (natural glass), Man-made glass
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