Malachite and alexandrite are both beautiful stones which have been popular for centuries among those able to afford them.
While they are very different minerals, they are easily confused for one another in some circumstances.
Let’s look at some key features of each and how you can recognize genuine stones, then discuss identifying malachite and alexandrite.
Malachite vs Alexandrite: Explained
What Is Malachite?
Sometimes confused with emerald, Malachite is a mineral of green copper carbonate hydroxide.
Chemically, it can be represented as Cu2(CO3)(OH)2.
Its technical composition obscures the fact that it’s one of the most unique and beautiful stones in the known world – and also one of the most imitated.
Malachite has been a popular mineral for gemstones and small sculptures for thousands of years.
It is easily ground into powder form and was for many years used for pigmentation or other coloring applications.
It retains its color very well over time no matter what form it’s in, making it even more popular with artists, artisans, and elites over the centuries.
At one time malachite was mined as a source of copper, but that’s no longer considered cost-effective – particularly given its ongoing popularity for use in jewelry.
You can recognize malachite by the many rich shades of green typically banded or swirled together.
Patterns in polished stones range from tight lines of varied widths to complex patterns resembling all-green tie-dyes or cells dividing under a microscope.
Emeralds may offer more shine and jade may be more precious, but malachite looks and feels solid – almost confident.
Perhaps that’s why it has for so long been considered by many to be a symbol of transformation or growth.
True malachite is heavier than it looks and feels hard to the touch in either rough or polished form.
It is almost always completely opaque.
Patterns and stripes will appear random and “imperfections” are both universal and desirable.
Malachite will remain cold in your hands even after holding it for several minutes.
If what you’re holding seems comparable in weight or warmth to glass or hard plastic, it’s probably not genuine malachite.
Malachite is found underground in caves or other natural formations, usually in stalactite form.
Its Mohs hardness is typically between 3.5 and 4.0, making it rather soft for many uses.
It’s therefore not unusual to find it protected by resin or a thin layer of wax to avoid unintentional damage.
What Is Alexandrite?
Alexandrite is a rare variety of chrysoberyl.
It’s formed when beryllium and aluminum combine with chromium and a smattering of other essential elements to form a very hard (Mohs 8.5) but very attractive mineral.
The chromium requirement is what makes alexandrite so unusual, and thus so valuable.
Only rarely does chromium appear alongside the other necessary elements and under the required conditions.
Alexandrite was first discovered in the Ural Mountains of Russia.
It has since been located in limited quantities in Sri Lanka, East Africa, and parts of Brazil, but it’s uncertain how long current supplies will last.
For most gem lovers, the most immediate attraction of alexandrite is the way it changes color based on the lighting to which it’s exposed.
Although sometimes described as “emerald by day, ruby by night,” the reality is slightly more complicated.
The color changing effect is a result of the way the mineral absorbs and reflects different types and intensities of light.
The same stone may express different shades of color when viewed at different angles even under the same light.
Because of this, alexandrite is considered by some to represent balance or the healthy blend of many different sides of a person or an issue.
In full daylight or strong fluorescent light, most true alexandrite exhibits a rich green or greenish-blue hue, much like an emerald.
Under incandescent lights or light from natural flame, the stone appears a rich purplish-red, sometimes described as “ruby red.”
(Some varieties produce pink or yellowish-gold in the daytime and a smokey blue by artificial light instead.)
Natural alexandrite is quite rare and most of what’s sold as alexandrite are manmade replications of varying quality.
This isn’t always a negative – some of the imitations are quite good – but it’s important to know what you’re actually getting.
Alexandrite’s properties make it ideal for use in medical lasers.
Alexandrite lasers are used to repair certain types of skin damage or remove unwanted tattoos.
Between its status in high-end jewelry and its medical applications, you’re unlikely to find it lying around with other pretty minerals waiting to be added to someone’s grab bag.
Identifying Malachite vs Alexandrite
It’s possible to confuse malachite and alexandrite at first glance, particularly if the alexandrite is presenting a nice rich green at the time.
Both certainly offer seductive colors even in rough form.
Both are most commonly used in jewelry, although malachite is often cut into beads or cabochons while alexandrite is typically cut like any other gem to be set.
Upon closer inspection, however, the bigger challenge is usually separating genuine malachite or alexandrite from the many imitations science has created over the years.
With a little time and care, you should have little problem distinguishing malachite from alexandrite.
In its natural form, malachite is almost always completely opaque while one of alexandrite’s defining features is the way it interacts with light.
In other words, you usually can’t see light through malachite but you can almost always see light through alexandrite.
In cut or polished form, the difference is even more pronounced.
Malachite offers a solid range of greens, from dark forest to almost lime, in random patterns or scattered lines.
Alexandrite “sparkles” or seems to “shine,” similar to emeralds, rubies, or sapphires.
Of course, the most pronounced difference is how each reacts to light.
Malachite will remain essentially the same whether you’re indoors or out, in natural lighting or under a bulb, by candle or by flashlight.
Alexandrite will look quite different depending on the light source feeding it.
That is, in fact, a large part of its appeal.
Finally, the hardness of the stones will end the inquiry, assuming you can actually test out the hardness.
Malachite is quite soft, while alexandrite is quite hard.
Malachite should be reasonably easy to scratch with a piece of quartz (hardness 6-7), while alexandrite should not be scratched with a piece of quartz.
There’s no shame in asking questions or taking a closer look anytime you’re presented with what could be a rare or precious stone.
With a little time and attention, however, distinguishing malachite from alexandrite itself should not prove too much of a challenge.