Can an iPhone detect metal?
An iPhone magnetometer measures the magnetic field near the phone. Some nearby magnetic objects can change that reading. The reading alone cannot identify an object, distinguish gold from other metals or tell you how deep something is buried.
What does µT mean?
µT means microtesla, a unit of magnetic-field strength. A higher reading indicates a stronger field at the phone; it is not a metal percentage, distance or object size.
How can I check a changing reading?
- Move away from speakers, magnetic mounts and other electronics. Remove a magnetic case if practical.
- Hold the phone in a consistent position and observe the current reading.
- Move slowly toward and away from the area, without changing the phone’s orientation abruptly.
- Return to the same place and direction. Check whether the reading returns to a similar range.
This comparison is an observation, not a certified calibration or proof of an object. The upcoming update adds an optional starting value and a guided comparison.
Why can a case or laptop affect the result?
Magnets in accessories and magnetic fields near electronics can change what the phone measures. A large reading near them does not establish that hidden metal has been found. Repeat the observation away from these sources.
Can it find gold, wires or a safe drilling point?
The app cannot reliably identify gold, determine depth, detect every metal or certify a wall as safe to drill. Use equipment designed for the specific inspection. Do not use a phone reading as a safety clearance.
What is available today?
The public 1.6 release shows magnetic-field readings with visual and sound feedback. Field Lens, saved scans and guided return comparison belong to the upcoming update and are not advertised here as released features.
What is this explanation based on?
Apple documents the magnetometer as magnetic-field data on three axes, expressed in microteslas. Object identification and depth are not outputs of that API.
Apple Core Motion: CMMagneticField · Public App Store listing