You can also try the following methods:

Chemical test: Using certain chemicals that react differently with zinc and uncoated metals. But this is more complex and not commonly used in everyday situations.
Weight difference: Galvanized wire may be slightly heavier due to the added zinc coating, though this might not be very obvious without precise measurements.
Electrical resistivity test: There may be a measurable difference in electrical resistivity between galvanized and non-galvanized wire, but this requires special equipment.
Surface hardness test: The zinc coating can make the surface a bit harder, which could potentially be detected through a hardness test.

Another way is to look for any signs of corrosion or rust. Galvanized wire is much less likely to show significant corrosion or rust compared to a non-galvanized wire over time. If a wire appears relatively clean and free of rust despite being in an environment where corrosion is common, it could be an indication that it is galvanized. Additionally, you can check for any marking or label on the wire packaging or along the wire itself that might indicate it is galvanized. Sometimes manufacturers will include such information to help identify the type of wire.

Additional Resources

How To Distinguish Between Galvanized Welded Wire Mesh And Stainless Steel Welded Wire Mesh
How can you tell if a piece of iron has been galvanized
How can I tell if a piece of steel has been galvanized
How to Test to See Whether Steel Is Galvanized