Try tapping your sample a few times with a hammer. Nonmetal minerals are easily broken, while metals will hold up to repeated strikes. Additionally, nonmetal minerals are insulators rather than conductors, meaning they don’t transfer heat or electricity well. One simple way to test the conductivity of a mineral is by making it part of a circuit with a battery pack on one end and an electric bell or light bulb on the other. If your sample is a metal, the electricity will pass through it and activate the bell or bulb. [2] X Research source
Ferrous metals are those that contain iron, including raw iron, carbon steel, pure nickel, and various iron alloys. [4] X Research source Most common metals are nonferrous, including lead, aluminum, nickel, copper, brass, titanium, and zinc.
Certain metals, like lead, aluminum, magnesium, and alkali metals, are so soft that you can actually cut them with a knife. [6] X Research source It can be difficult to leave so much as a scratch on harder metals like iron, stainless steel, titanium, and various alloys.
In order to accurately compare the weight of your samples, it’s important that they be close in size.
Once the test is complete, the machine will automatically generate a numerical Rockwell Hardness Rating for your sample. Compare this number to a chart listing the ratings of various metals to determine what type of metal your sample most likely is. A rating of 20-25 on the “B” scale, for example, corresponds to aluminum. [9] X Research source There is also another type of hardness test known as the Brinell Hardness Test. This version uses a rounded metal test point rather than a sharp one, but the basic principle is the same. [10] X Research source
Wrought iron sparks, for example, have long, straight shafts and burn a bright yellow-white, while the sparks from high-carbon steel are pure white and form erratic branching patterns. Other machinable metals have their own unique spark profiles that can aid in their identification. [12] X Research source If you have access to the necessary equipment and experience working with different metals, a quick spark test can tell you almost everything you need to know about the material you have on your hands. Before you begin grinding your test metal, pull on a pair of thick, durable welding gloves and some safety goggles to protect yourself from flying sparks.
You can purchase nitric acid online from laboratory supply stores that carry test chemicals. Remember: not all that glitters is gold. A metal that looks like gold could just as easily be brass, pyrite (a mineral sometimes referred to as “fool’s gold” for its resemblance to the metal), or some sort of composite. Silver also tarnishes when exposed to the elements, producing a finish similar to the patina that forms on brass.
Most types of iron exhibit an angular, crystalline structure when filed or broken. This is especially true if your sample hasn’t been processed or blended with other metals. Items like household fixtures, tools, electric motors, and old-fashioned furniture and appliances often contain some percentage of iron. Cast iron has a Rockwell Hardness Rating of 86.
If you have a nonferrous metal with a silvery hue, there’s a good chance that it’s either tin or aluminum. [16] X Research source Stainless steel is commonly used for cookware, eating utensils, household appliances, building materials, and storage containers. Stainless steel has a Rockwell Hardness Rating of 88.
If you’re still not sure whether the metal you have is copper, place it outside for a few days. Copper turns green as it oxidizes. Thanks to its exceptional conductivity, copper is a go-to metal for manufacturers of pipes, electrical wires, roofing materials, and internal components for computers and other electronics. [18] X Research source Copper has a Rockwell Hardness Rating of 10.
Bronze is often slightly darker than brass, as it contains a higher proportion of copper. Brass and bronze are used everyday to make things like musical instruments, pipe fittings, and manifolds. Brass ordinarily has a Rockwell Hardness Rating somewhere between 55 and 65, while the HRC of bronze can range from 42 to 78.
One surefire way to find out whether a given metal is lead is to evaluate a small sample using a lead testing kit, which you can pick up at your local hardware store. Follow the provided instructions carefully—most kits display a red or pink color when lead is detected. [22] X Trustworthy Source Consumer Reports Nonprofit organization dedicated to consumer advocacy and product testing Go to source It’s a good idea to wear gloves anytime you’re handling a metal that you think might be lead, as the metal is highly toxic. While not as common as it used to be, lead can still be found in certain industrial materials, such as electrical sheathing, car batteries, and soundproofing. In the past, it was a popular ingredient in everything from interior paint to children’s toys. Lead has a Rockwell Hardness Rating of 5, the lowest of all metals.
Aluminum is also nonferrous, which means that a magnet won’t stick to it. Another remarkable characteristic of aluminum is that it doesn’t rust. If all else fails, leave your metal outside for several days or weeks. When you come back to collect it, look for traces of red or brown that might point to oxidation. [24] X Research source Mailboxes, ladders, trash cans, metal fencing, bicycle frames, staples, and hubcaps are all made from aluminum, which is lightweight and holds its shape well when molded. Aluminum has a variable Rockwell Hardness Rating of 20-40, depending on how it’s processed and whether it’s combined with other metals.
Inspect your metal closely for grade markings. Scraps of processed titanium may be stamped with a string of numbers and letters indicating their exact composition. Titanium is prized for its high strength-to-weight ratio, which makes it a perfect addition to building materials, aircraft components, golf clubs, jewelry, eyeglass frames, and even artificial hip and knee joints. [26] X Research source Titanium has a Rockwell Hardness Rating of 80, coming in just behind cast iron and stainless steel.
