What do Detectors Detect

What do Metal Detectors Detect? [Ultimate Guide!]


What do Metal Detectors Detect

One of the first questions I’ve personally asked while being interested in Metal Detecting as a hobby is about the types of items that detecting machines could actually find!

That’s why, I’ve decided to put together this complete article in which I share all what I’ve learned … Hopefully, this will save you time and effort searching in other sources …

… So, what do metal detectors detect? Detectors can detect any object that can conduct electricity (Silver, Iron, Gold, Lead…)! As the machine’s coil emit an electromagnetic field, this will trigger electric current in the target item which will also cause a change in electromagnetic field’s shape. The machine can sense this change and will let you know.

This was my simplified answer to this question so you could have a clear idea! However, I would love to give you more details regarding the different items that your device could easily find, and others that could find, but hardly …

… Also, it is important to know the limitations of your machine and what it can’t find … As well as other helpful details that you should know as a hobbyist!

Do metal detectors detect ALL Metals?

Even if this question seems somewhat obvious, yet, it is a good and tricky question at the same time … That’s why I wanted to address it early in this Post!

Before that you should know that Metals are materials having lustrous appearance with ability to conduct both heat and electricity… They have polished appearance possessing the property of malleability and ductility …

…. They are generally classified under 2 different categories:

  • Ferrous metals: They are magnetic in nature as they are totally or partially contained in terms of iron … This category in generally considered to hold the least amount of value … Not always but most of the time!
  • Non-ferrous metals: Don’t contain iron thus with no magnetic property and they have high resistance against corrosion. Gold is a non-ferrous metal by the way!

Detecting machines should generally be able to pick both ferrous and non-ferrous metals! So, they can detect all metals, Right? Actually, Wrong! There are few exceptions to that and one of them is the notorious Stainless Steel …

… Simply, because it has a poor electrical conductivity that makes the task much harder for your device!

However, you should keep in mind that this applies mainly detectors that have a low frequency, around 3kHz… However, if you are using one with a mid-range or high frequency, then you should be able to pick up all metals pretty easily including stainless steel!

Another factor that you should consider is the fact that the closer the detector to the target, the stronger magnetic field is put on your metallic target, thus, the sound should be felt louder …

… That is, if your target is located deep, then it will be harder to sense it … I will address this later in this Post!

Keep in mind that to be able to detect all possible metals, you will need a multi-terrain/multi-purpose machine! And one of the best examples of that is the Garrett AT Pro (Check it Here on Amazon!)

Most valuable metals that detectors can detect

Most valuable metals fall into the non-ferrous category! There are many examples of valuable metals which you should generally target as much as you possibly can…

… The most valuable items that you can find are generally made from these metals:

  • Gold: You can find it in jewelry as well as in pure form like gold nuggets! If you want to be more knowledgeable about that, I encourage you to have a check at this Gold Metal Detecting Guide
  • Copper: Some people may not consider it to be that valuable, but the trick is when you are able to gather this metal in high quantities … Then you could sell it and put some serious cash into your pocket.
  • Silver: It is rare to come across this metal in its pure form, yet finding it in jewelry and relics is much more common.
  • Meteorite: This is not a metal, but its composition is mainly based on different metals like iron, nickel as well as others! Its value is recognized mostly by collectors and depends on many factors like the size, weight, origin as well as the shape. Learn more about metal detecting for meteorites!
  • Platinum: Some people confuse it with white gold, yes they look almost the same, yet they are 2 different things! When it comes to value, platinum is definitely no joke … Indeed, it is even more valuable than 18K white gold! This is due to its superior appearance and durability …
  • Tungsten: This is not as valuable as gold for example, yet it is still considered to have a good value in it because of its robustness! There has been a trend these last years using this metal for jewelry.

You can find more valuable items than what I’ve just listed!

You can also find gemstones using your detection device, not directly though, as they cannot conduct electricity.  Yet, keep in mind that mineralized soils with a good and frequent gold presence in them are usually a host for quality and highly valuable gemstones too!

If you are not really familiarized with those, below a little list of some gems you might pick up if you are knowledgeable and lucky enough:

  • Diamond: when you hear the word gem, then diamond is probably the first word that pops up to one’s mind. It is a high concentration of carbon mineral and holds an unbelievable value in it!
  • Alexandrite: This is pretty much a magical gem, it has a changing color depending whether you see it under the sunlight or the lamplight. Indeed, under the sun it looks rather bluish and under a lamp it looks like a red gem.
  • Garnet: you can find it in many different colors from red to green to orange to other colors! This gem is often associated to some superstitious beliefs, that I personally don’t believe, yet it is a lovely gem!

Also, keep in mind that to be able to find these kinds of highly valuable targets, you will need a Gold Detection Device! And one of the most used ones among hobbyists is the Garrett AT Gold (Check it Here on Amazon!)

Least valuable metals that your detecting device can find

Apart from the valuable metals and gems (ohh, I love gems) that I’ve just listed below, there are others that hold, let’s say, average or even low value in them …

… This, is something that comes with the territory and that you should be aware of … Below a list of these elements:

  • Brass: Could hold value if you’ve come across an aircraft made of brass!
  • Titanium: this is probably the least valuable item in this short list, yet it you come across a
  • Bronze: if you’ve picked up a bronze aircraft then there you go! Otherwise, bronze is not that valuable …
  • Aluminum: As a beginner your beloved machine will pick up a ton of aluminum caps and cans … That will be frustrating for sure, but it’s also a lot of fun!
  • Lead: in itself not that precious, however, if you come up with a WW relic like some old bullet, then that’s hold an historical value.
  • Nickel: Same as the previous one, unless you find an old nickel coin! Also, many moden and old keys are made out of nickel.

These metals are generally found in their pure form in mines or metal deposits. Alloys can be detected if one of their composition is iron or is magnetic in nature…

… For example, Nickel and cobalt or alloys containing nickel or cobalt can also show response towards detectors due to their magnetic nature even though there is no iron in their composition.

Nonmagnetic metals like copper, aluminum, lead, tin, titanium, zinc and their alloys also are detected simply because of their good electrical conductivity.

A good machine that I recommend to find these kinds of targets is the Fisher F22 (Check it Here on Amazon)! It is adapted for those who are on a budget …

Items that metal detectors can’t detect

After you’ve had a solid idea on what you can actually pick up using your device, I feel it is also interesting to have an idea on what it actually can’t detect!

Again, these machines operate on the mechanism of electromagnetism. They emit time varying electromagnetic fields and then detect the waves coming back from the metallic objects…

… Thus, the items which are not detectable are those that lack these physical capabilities … Below examples of what your lovely machine just can’t see:

  • Pearls
  • Glass and glass objects
  • Papers
  • Stones and sculptures or figurines made up of stones
  • Bones
  • Liquids
  • Plastic
  • Raw diamond

I’ve said this before … Gemstones like diamond are not directly detected as these are nonmetal items but they can possibly be found near gold mines or volcanic pipe lines!

Factors that limit your machine’s performances

After you’ve learned what detectors can and cannot pick up, you should also learn about a number of conditions that limit its performance!

Unfavorable weather conditions could be a big hurdle … For example, if the soil is too dry or too wet then could cause it to underperform a little bit …

… Another big challenge is when you are dealing with mineralized soil! Indeed, there are 3 types of mineralized soils that you should understand:

  • Conductive salt: where the ground is rich in salt particles that can conduct electricity.
  • Magnetic ground: when the soil is rich in ferrous particles like iron that could easily be attracted if you run a magnet on them.
  • The 3rd time is the worst; it is simply a combination of both previous grounds.

The main challenge that comes with that is that a machine with low or mid-range frequency will easily detect false signals! This will simply prevent you from digging the good stuff …

… This won’t be that big of a deal if you are using a solid machine like a CTX 3030 or an AT Max or even an Equinox 800 (Check it Here on Amazon)!

I highly invite you to learn what can make a metal detector even more powerful!

Can detectors find you items underwater?

There are two main types of devices that use waterproof detection technologies in order to detect items underwater …

  • Pulse Induction
  • Very Low Frequency

Pulse Induction: Are known to transmit a series of quick electronic pulses which are highly sensitive to precious metals like gold nuggets! These electronic currents are not affected by wet salt sand and minerals present in the ground or under water …

… This type is ideal for detecting metals in salt water beaches and when diving. They can operate very deep and suitable for tough ground mineral conditions!

Very Low Frequency: This type, on the other hand, operates in low and/or mid-range frequencies! They are generally used for coin shooting and to find relics and all sort of jewelry…

… It is suitable to use them in Clearwater as it they are affected by the presence of minerals in the ground. Salt water or water having high mineral content can affect their performance but have discrimination functions that will enable you to limit false signals.

Can detectors detect smaller objects?

Small items can be found with the help of detectors as long as they can operate on high frequencies Like the CTX 3030 (Check it Here on Amazon!) … This will give them a solid sensitivity to the smaller items like gold nuggets or even gold dust!

Hand held detectors can be used for picking up small objects as they contain a sensor probe with a hand held device which when sweeps over any surface fives signal if any small metal object is present…

Needle or staple detectors are also highly sensitive and used for detecting objects like needles, staples, iron nails or other similar small metal objects…

… On the other hand large detecting devices have lower sensitivity and thus are unable to detect smaller objects. White’s TM 808 for example is specifically designed to find large targets like:

What about their ability to find objects deep underground?

Detection devices are able to see objects that are buried under large depth … For example there are some machines that can detect objects at a maximum depth of 15 inches if you are dealing with a clean ground condition …

… However, if the ground is trashy, the depth could be reduced to 7, 8 or 10 inches!

There are ways to improve the depth one of which is to use a larger coil! Thus, you will cover more space while swinging and find things much deeper …

… In fact, the larger is the size of the coil, the deeper you device can go!

Examples of these are:

  • Garrett ATX Pulse Induction Military Grade (Check it Here on Amazon!) is able to pick up gold nuggets up to 24 inches deep. It can find all kind of large objects up to 3 feet of depth depending on the settings and the electrical conductivity of your target!
  • The Garrett Ace 350 (Check it Here on Amazon) Handheld, on the other hand, can be used to find even small objects like coins up to 11 inches and quarter up to 17 inches of depth. They provide good performance even in mineralized grounds and are able to differentiate between target items or metals or iron objects. The electronic pinpointing unit makes it precise to see smaller objects even at such depths.

Want to learn more about metal detector’s abilities to go deep?! Then have a look at this detailed Post!


If you are a total beginner who is just getting familiar with this hobby, then I am glad that you’ve taken the time to go through this Post …

… Simply, because I know that understanding these basic information I’ve shared above could be, sometime, a little confusing or annoying to go through!

Other than that, if you still didn’t get your first detector and wonder what machine you should pick, then you definitely should check this solid guide on choosing the right metal detector

… You will learn a ton of good stuff there!

About the Author

Carissa Harmer

Carissa is the huge metal detecting enthusiast that loves collecting coins. She is also highly interested in other treasure hunting activities like magnet fishing and gold prospecting/panning.