Rock Discoveries

Geologists Licking Rocks: The Unusual but Effective Practice in Mineral Identification

Licking Rocks and Minerals in Geology

Have you ever heard of someone licking a rock? It may seem bizarre at first, but in the field of geology, this is a common practice used to identify certain minerals.

Geologists use a range of techniques to identify geological specimens, with licking being one of the easiest and most effective ways. In this article, we will explore the use of licking in geology, its effectiveness, and the dangers associated with it.

Identification of Minerals

When it comes to identifying minerals, licking can be an effective way to determine the type of mineral. It is particularly useful for identifying halite, sylvite, quartz, calcite, and gypsum.

These minerals all have distinct tastes, textures, and mineral structures that can be identified through licking.

Halite and sylvite are two of the most commonly identified minerals through licking.

Halite, or rock salt, has a distinctive salty taste that is easy to identify.

On the other hand, sylvite, or potassium chloride, has a bitter taste that is harder to distinguish. The ability to identify halite and sylvite through licking is especially useful in the context of salt mining.

Calcite and gypsum are two other minerals that can be identified through licking. Calcite has a smooth, creamy texture, while gypsum has a chalky texture.

Quartz, one of the most abundant minerals on Earth, has no distinguishable taste or texture.

Differentiation of Grain Size

Aside from identifying minerals, licking can also be used to differentiate grain size. Siltstone and shale are two sedimentary rocks that can be distinguished through licking.

Siltstone has a gritty texture, while shale has a smoother texture.

Identification of Porous Rocks and Minerals

Licking can also be used to identify porous rocks and minerals, which are characterized by small open spaces within their structure. Chrysocolla, a type of copper mineral, has a distinct greenish-blue color and powdery texture.

Kaolinite, a clay mineral, feels smooth and powdery to the touch.

Danger of Licking Toxic Minerals

While licking can be an effective way to identify certain minerals, it is important to note that this practice can also be dangerous. Some minerals are toxic and can lead to serious health problems if ingested.

These minerals include arsenic, lead, mercury, antimony, thallium, uranium, and copper. Arsenic, for example, is a highly toxic mineral that can cause damage to the nervous system, skin, and other organs.

Lead poisoning is another serious health concern that can result from licking lead-containing minerals. Mercury, antimony, and thallium are also toxic minerals that can cause a range of health problems.

In addition, uranium is a radioactive mineral that can emit harmful radiation when ingested. Copper, while not as toxic as some of the other minerals mentioned, can still cause an upset stomach if ingested in large amounts.

Evaporite Minerals

Evaporite minerals are chemical sediments that are formed when dissolved salts are left behind as water evaporates. These minerals are commonly found in areas with high evaporation rates, such as deserts, playas, and salt lakes.

Some of the most common types of evaporite minerals include carbonates, sulfates, and chlorides. Definition of

Evaporite Minerals

Evaporite minerals are formed through a process known as evaporation.

When water evaporates, it leaves behind any dissolved minerals and salts, which eventually form crystalline deposits. These deposits are then known as evaporites.

Common Types of

Evaporite Minerals

Carbonates are one of the most common types of evaporite minerals. Some examples of carbonate evaporites include limestone, dolomite, and anhydrite.

Sulfates, such as gypsum and anhydrite, are also commonly found as evaporite minerals. Chlorides, including halite and sylvite, are also frequently found in evaporite deposits.

Identification of

Halite and Sylvite

Halite and sylvite are two of the most commonly identified evaporite minerals. As mentioned earlier, halite has a salty taste, while sylvite has a bitter taste.

Halite is the mineral that forms rock salt, while sylvite is used to produce potassium fertilizers and other industrial products. In conclusion, while licking minerals in geology may sound unusual, it can be an incredibly effective way of identifying certain minerals.

From distinguishing grain size to identifying porous rocks and minerals, the use of licking has a range of applications in the field of geology. However, it is important to remember that certain minerals are toxic and can be harmful if ingested.

As always, it is essential to exercise caution and safety measures when conducting fieldwork in geology.

Geologists Licking Rocks

Geologists have been known to lick rocks as a way of identifying certain minerals. This may seem like an unusual practice, but it is a quick and easy way for geologists to determine the type of mineral they are working with.

In this article, we will explore the importance of licking rocks for geologists, the process of licking rocks, and the types of rocks and minerals to avoid licking.

Importance of Licking Rocks for Geologists

Licking rocks is a quick and efficient way for geologists to express-identify the mineral group to which a specimen belongs. This aids in the interpretation of the environment in which the rock was formed and the other minerals present in it.

Licking can be very useful for mineralogists working on evaporites. Evaporite minerals like halite, sylvite, and other halides, carbonates, and sulfates have characteristic tastes which allow geologists to identify them quickly and efficiently.

The Process of Licking Rocks

The process of licking rocks typically involves light-coloured semi-transparent rocks, which can be clearly seen through a thin surface. The rock is licked with the tip of the tongue for a short duration, and the taste-based response recorded.

The taste should be noted immediately upon contact, as a lingering taste can be from previous minerals or bacteria present on the rock surface.

Types of Rocks and Minerals to Avoid Licking

While licking rocks can be a useful tool for geologists, there are certain types of rocks and minerals that should be avoided. Brightly coloured minerals, such as those with a metallic luster, should not be licked, as these often contain toxic substances.

Additionally, minerals that are known to be toxic such as copper carbonate hydroxide (

Malachite) and lead sulfide mineral (

Galena) should not be licked.

FAQs about Licking Rocks and Minerals

Rose Quartz

Rose Quartz is a mineral that geologists may come across and the question often arises as to whether it is safe to lick. Unlike many other minerals, Rose Quartz has no taste.

Additionally, it is a very hard mineral, and licking it is not recommended as it could damage the tongue.


Malachite is a bright green mineral that is often associated with copper deposits. It is known to be toxic, containing copper carbonate hydroxide.

As such, licking malachite is strongly discouraged, as it can lead to health issues.


Galena is a lead sulfide mineral that is known to be toxic.

Galena contains lead, which can be dangerous if ingested.

It is important to note that licking

Galena can lead to serious health problems, including lead poisoning.


Halite is a mineral that is commonly identified through licking. It has a distinctive salty taste, which is a diagnostic feature.

Halite, also known as rock salt, is often mined for use in road salt and other applications.


Gypsum provides another example of a mineral that geologists can identify through licking. Unlike halite, gypsum has no taste.

However, it can be differentiated from halite by its texture it feels much softer.

Gypsum is a common mineral that is often used in building materials.


Licking rocks can be a useful technique for geologists and mineralogists to identify minerals while working in the field. It is important to note, however, that not all minerals are safe to lick, and certain minerals can lead to serious health problems if ingested.

By being aware of these risks and following proper safety procedures, geologists can continue to use this technique as a quick and efficient way of identifying minerals. In conclusion, licking rocks is a unique and effective practice used by geologists to identify minerals in the field.

However, it’s important to be cautious of the specific rocks and minerals that are best avoided to ensure safety. By using this technique carefully and responsibly, geologists can continue to benefit from its quick and efficient nature and gain insights into the environment in which the rock was formed.


Q: Is it safe to lick

Malachite? A: No,

Malachite is a known toxic mineral containing copper carbonate hydroxide.

Q: Can all minerals be identified by their taste? A: No, not all minerals have a distinguishable taste.

Q: How can I differentiate between

Halite and

Gypsum? A:

Halite has a salty taste, while gypsum has no taste and feels much softer.

Q: Are brightly coloured minerals safe to lick? A: No, many brightly coloured minerals contain toxic substances and should be avoided.

Q: What should I do if I accidentally ingest a toxic mineral? A: Seek medical attention immediately.

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