Searching for valuable rocks and minerals is an exciting and engaging hobby that sometimes requires lots of cash. But if you learn about the most valuable minerals, you can turn this pleasure into a profitable discovery.

Rock hunting, or amateur geology, has become quite popular among passionate people of all ages who want to spend their time exploring the outdoors. You can start your searching adventure with a few tools, such as a hammer, a bucket, magnifying glass, and some safety goggles. But be aware of local regulations which may prohibit the collection of rocks and minerals, especially rare fossils.

Now, I don’t want you to make the mistake of thinking that all rocks and minerals are worth a great deal of money – that is definitely not the case. Thus, it is essential to understand the particularities of an antique stone versus an ordinary mineral. So what constitutes a precious rock or mineral? What are the characteristics that reveal the value of a gemstone?

We will help you to find out if your rock collection is valuable, and learn to evaluate each stone properly before selling them on suitable platforms.

Minerals, Rocks, And Gemstones: Main Differences

Before discussing the most valuable rocks and minerals, it is useful to have an overview of their main characteristics to help you distinguish them better.

Minerals

Mineralogy is the science of minerals encompassing the range of ways minerals are shaped due to geological processes. Minerals are naturally formed inorganic substances. They have particular chemical and physical compositions with uniquely ordered atomic and crystalline structures. There are over 2,000 known minerals, each of them with a specific, identifiable configuration.

The easiest way to identify minerals is based on these seven factors: streak, color, cleavage, luster, hardness, fracture, and crystal shape.

Some of the most precious minerals include diamonds, emerald, sapphire, ruby, and red coral.

Rocks

Rocks are mineral accumulations without particular chemical compositions. When it comes to minerals, we can talk about thousands of shapes and textures, from the purest elements to a fusion of silicates.

Conversely, we can separate rocks into three types:

  • Igneous
  • Sedimentary
  • Metamorphic

The study of rocks is called petrology.

Here are a few interesting examples of rocks you may (or may not) have heard of: agate, amethyst, quartz, tanzanite, zircon, turquoise.

Gemstones

Scientists classify some rocks or minerals as crystalline and amorphous gemstones. Crystalline gemstones are minerals with stable and definite atomic structures.

However, a mineral should have both aesthetic and economic value to be classified as a gemstone. Therefore, gems are some of the most precious minerals that are carefully selected to be cut, polished, and then used usually in jewelry making.

Some well-known examples of gemstones are garnet, ruby, and emerald.

To be classified as a gemstone, a mineral has to have economic and aesthetic value.

Even rocks can be defined as gemstones. But in order for this to happen, they have to have decorative applications, such as lapis lazuli.  Although they do not have the ideal crystalline structure, some organic materials have been labelled as gemstones. This applies to amber and coral.

The Rarest And Most Valuable of Them All

Gemstones are the rarest of them all; however, this statement is only partially true. Let’s take amethyst, which used to be a rare gemstone – it is now easily found.

The ideal way to distinguish minerals from gemstones is based on their composition and jewelry-making usage. Keep in mind that minerals are mainly crystalline. If a gem is crystalline, this means it is a mineral. The same principle applies to rocks as well.

How To Identify The Most Precious Rocks And Minerals

The most common way to recognize rocks and minerals is by color, sheen, specific gravity, cleavage, crystal shape, hardness, streak, crystal structure, habit, density, transparency, and fluorescence. Let’s get into more detail…

Color

The color of rocks and minerals can be a deceiving factor in value. Even minerals with the same chemistry can have different colors generated by minor impurities in the crystal composition (like particles of titanium, iron, or manganese).

For instance quartz can be either clear, red, yellow, white, green, brown, grey, purple, or sometimes even black.

Sheen

Luster or sheen describes the quantity of light reflected from the rock’s or mineral’s surface. This characteristic is essential in determining the value of a mineral, as it indicates the quality of the rock’s surface, disregarding the color. There are two principal divisions of sheen: metallic and non-metallic.

Nevertheless, different terms are used to describe non-metallic lustre, such as earthy, glassy, greasy, adamantine, pearly, resinous, and even silky.

Specific Gravity

Particular Gravity
Image Source: @swatiandsunaina

The specific gravity is the relative density of a material in relation to a reference substance, usually water. The best method to determine the specific gravity is to weigh a sample in the air, then re-weigh the same sample while immersed in water.

The specific gravity is then calculated by simply dividing the weight in the air by the weight in water.

Now, water has a specific gravity of 1, while gold’s specific gravity is around 19. Usually, minerals have a specific gravity that ranges from 1.5 to 19.5.

Cleavage

When a crystal breaks, it splits along some cleavage planes, also known as straight faces. These tiny parts are weak because of a crystal’s atomic structure. Mica, a shiny silicate mineral, has a cleavage plane that allows it to break into very flat sheets.

Crystal Shape

Crystal shape
Image Source: @jhbnyc

Each mineral has a specific shape that, when crystallized, reflects the internal arrangement of its atoms. While some crystal shapes are easier to recognize due to their popularity (see octahedral diamond), others have more specific particularities. Most of the ideal crystal shapes can be classified as geometric shapes.

Hardness

Rocks and minerals can be easier to identify based on their relative hardness. The simplest way to tell if a substance is harder or softer than a reference material is by its ability to scratch another substance. To measure the hardness of rocks and minerals, specialists use the Mohs Scale of Hardness, a relational scale where 1 stands for minor hardness and 10 for the hardest mineral.

For instance, quartz has a hardness of 7, so it will easily scratch any other mineral that scores less than this value.

Diamonds have the highest hardness so that they can scratch any other mineral. There are different materials used to determine the hardness of rocks and minerals, like steel nails and fingernails.

Streak

Professionals and scientists generally use streak more often than color as a reliable identification mark for minerals. But what’s the difference? The streak is the specific color of a powdered mineral and can be determined by scratching a sample on an unglazed white porcelain slate (in other words, a streak plate). Even with some impurities in the mineral’s body, the color of the streak will remain consistent.

Crystal structure

Atoms are generally organized in a crystal lattice structure and compose a common internal framework. Everything is symmetrical within the lattice and quite fascinating. But why is crystal structure so crucial in valuing a rock or a mineral?

Crystal composition influences different properties of minerals, like hardness, cleavage, and crystal shape.

Habit

Habit
Image Source: @zeolite_minerals_ajanta

The form or the habit refers to the particular shape in which minerals and rocks usually form. This shape is very characteristic and can be spectacular, like this mesolite sample above.

Most minerals do not have a perfect shape, especially the individual crystals. Usually, these are  aggregates of crystals with a special appearance, such as tiny rounded balls, needle-like masses, or a radiating form like a fan. Many minerals may display multiple habits, not just a single one.

Take a look at the mesolite above; notice the acicular habit and the needle-like crystals.

Density

Density
Image Source: @zangal_gems1

Density represents the mass per unit volume, and calculating it is a simple process: a precise measurement of volume and mass.

Precious stones and minerals, like zircon, rubies, and diamonds, are the easiest to identify when calculating their density.

Transparency

Transparency
Image Source: @crystallynn.co

Transparency refers to the clarity of a mineral. Just hold the mineral up to a source of light and if you can see through it it means the mineral is transparent. If a mineral transmits light, yet you cannot see through it clearly, experts call it a translucent stone.

On the other hand, if a mineral does not emit light, it is termed opaque. As an example, let’s take quartz: it can be transparent or perfectly opaque.

Fluorescence

Fluorescence
Image Source: @spiritualmineral

Some minerals show a distinctive color once placed under ultraviolet light (for instance, the green or blue glow of fluorite, the green radiance of willemite, even the pink glow that comes from manganese-bearing calcite).

The color of rocks and minerals can be different based on the type of ultraviolet radiation they are placed under (i.e. short-wave or long-wave).

Most Valuable Gems, Minerals, And Rocks

People most probably think about diamonds when someone talks about “the most valuable rocks and minerals.” But diamonds are not even in the top 3.

The list below might surprise you regarding the potential inherited or collected minerals in your possession.

Rubies

Rubies
Image Source: @ensen_jewellery

Rubies are the fifth most expensive rocks in the world. Although, at first sight, rubies are tiny and plentiful, these red gems’ quality is what establishes their price. The largest, blood-red rubies with clean cuts are the most valuable.

It is impossible not to recognize the vibrant red color of rubies and their pure shine. Rubies are classified like diamonds due to their color, quality, and grade. A pure ruby, without flaws, can be valued as high as a million dollars per carat.

To enhance their beauty, jewelry masters accompany rubies with other precious gems to enhance their beauty so that the final price gets even higher.

This spectacular piece of jewelry is centered around a massive ruby.

Blue Garnet

Blue Garnet
Image Source: @vwgoudsmid

Garnets come in various colors: you can find these gemstones in brown, orange, purple, red, green, and even yellow. However, the blue garnet is the rarest and most valuable of them all.

The very first blue Garnet was found in Madagascar, in the 1990s and then in other regions, like Russia, Turkey, and the US. Currently, this pricey stone can reach a million and a half dollars per carat. The presence of vanadium gives the intense blue shade during the developmental process.

Serendibite

Serendibite
Image Source: @d.simiohin

Serendibite is not a very common mineral; most probably only the very passionate mineral enthusiast will have heard about it. Why do you think this mineral is so rare? Well, because it can be extracted only in two places: Sri Lanka and Northern Buma.

Serendibite contains tiny amounts of molecules from other minerals, like silicon, oxygen, boron, aluminum, magnesium, calcium, or boron. All these have bound together in a complex formation process.

Red Diamonds

Red Diamonds
Image Source: @lavalierjewelry

Only red diamonds make it to the top five. A red diamond is in fact, the most expensive one in the diamond family, as well as the rarest of them all.

Only very few pieces are mined yearly in Australia at the Argyle Mine. Their unique purplish-red color is what distinguishes red diamonds from garnets or rubies.

Watch this collection of the most precious red diamonds in the world.

Jadeite

Jadeite
Image Source: @feicuijewellery

Finally, we have made it to the most precious mineral gemstone – Jade or Jadeite. One carat of this costly gem goes up to three million dollars. The rarity and beauty make this mineral so unique and pricey. This valuable stone was once used to make jewelry in ancient times.

Although these stones and minerals are the most expensive ones, there are other examples that are worth mentioning.

Emeralds

Emeralds
Image Source: @onegems

Emerald is a green gemstone that takes its color from to the amount of vanadium and chromium it contains. The usual hardness is around 7.5 and 8 on the Mohs scale.

Taaffeite

Taaffeite
Image Source: @zayangems

Taaffeite is the only gemstone identified from a faceted stone. It is mined in very few samples per year, making it one of the rarest gemstone minerals and, therefore, very precious.

Black Opal

Black Opal
Image Source: @sourcefield

Australian black opals are the most valuable and popular type of opal, characterized by a dark body tone, with dark grey and jet black varieties.

Red Beryl

Red Beryl
Image Source: @gemaofgb

Red Beryl is a scarce stone and a precious mineral with a unique appearance.

Musgravite

Musgravite
Image Source: @usia_modern

Musgravite is a rare oxide mineral in the category of gemstones. Due to its rarity, this mineral can be sold for roughly $35,000 per carat.

Fire-Opal

Fire-Opal
Image Source: @buckleyjewelry

Fire opal has a translucent body with warm colors, ranging from gold to orange. Sometimes, this stone can feature bright green flashes.

Valuing Precious Rocks and Minerals

Now that you know about some of the most valuable rocks and minerals, it’s time to move on to a more practical chapter. If you are interested in rockhunting, buying, or selling gems, you should know the signs to see if your rocks are truly valuable. You can do this by yourself or ask for professional advice. Here are some simple steps…

How To Value Rocks And Minerals by Yourself

With so many types of rocks and minerals, it is quite intimidating and overwhelming to know the specific characteristics of each item, making the process difficult. However, there are some factors that can determine the rock’s value which you can check by yourself:

Properly Identifying The Type Of Specimen

This is a crucial step, and truth be told is not an easy one. Nevertheless, knowing what your rock or mineral is called is essential. These two sources would be helpful: online communities, such as this Reddit Forum, or a local rock shop might help you identify your collection pieces.

The Origin Of Your Rocks

Among collectors, some areas of the globe are more desirable than others. This is why it is essential to have a well-cataloged collection with location information about each piece.

Get to Know the History of Your Collection

The history of rock will make it more valuable than if it is not labeled at all. You can take a picture of your rock, upload it on Google Images and hope to get a well-documented history of your minerals (unless you already know where and from who it came from).

Examine the quality

The harder a mineral is, the more likely it is to be valuable. Try scratching it with a fingernail, and if this works, then that is a very soft rock. If it scratches with a penny, its hardness would be at 3 Mohs, while a glass scratch would indicate a 5.5 hardness. Take a look at Mohs scale of hardness for more information on the hardness test.

Size and Weight

Size and weight might not be the most important parameters in valuing a rock or mineral, but they are significant. Generally, a high-quality, tiny specimen will fetch more than a lower-quality, large one.

Possible damage

Take a careful look at the rocks’ surface. If they are whole and intact, they will clearly be worth more than broken ones. Damage can mean internal fractures too. Sometimes, little flaws may add value and aesthetic quality. However, not all collectors would agree with this statement.

If you cannot value the rocks and minerals you have, here are some great places to get started:

Where To Get Rocks And Minerals Valued Professionally

One of the most common questions rock collectors ask is, “Where can I find a true authority to tell me what my minerals are worth?“. Unfortunately, there is no easy answer for this.

While it is easier to find somebody that can simply identify a quart or jasper, few would know the variations of materials based on pattern, origin, or color. There are also few lapidary artists that are able to custom-cut the rocks, as this is a highly-skilled job.

Firstly, look for a lapidary club in your area. Some may have shops or hold classes for people willing to learn. This club list is helpful. Another great resource would be a rock or mineral show near you, where professionals gather and display their collections.

Rocks shops might also have experts willing to share their knowledge. Keep in mind that some of them might charge you for this information.

Finally, although rare, a Rock and Mineral Museum may have a great collection of valuable rocks and minerals, and professionals to guide you.

Where To Buy And Sell Valuable Rocks And Minerals Collections

The best place to sell and buy valuable minerals collections would be reputable rock shows and shops. This would allow you to see the specimens and talk with the collectors personally. However, we live in the internet era, and lots of rock collectors have moved their activity online. Here is where you can find some trusted dealers and websites that specialize in rock and mineral deals:

eBay

If you are not able to find or sell your collection to the mineral shop or show, try the well-known auction site, eBay. The biggest benefit is the sheer volume of rock specimens, so you can find almost anything you want.

However, keep in mind that eBay is not all milk and honey, and, unfortunately, there are lots of fake sellers. Do some research first, and check the seller’s ratings to see if they are reputable suppliers.

Online Rock and Mineral Auction Sites

If you are looking for specialized dealers, check these trustworthy websites:

Etsy

One of the best tools to sell and buy your wholesale minerals and rocks is Etsy.com. It allows you to find a multitude of specimens.

Amazon

I would not recommend Amazon for selling and buying truly valuable rocks and minerals, but it can be a great source to develop this hobby and learn more about the gems’ particularities. You can also find rock and mineral ID guides for great prices here.

Bottom Line

So what makes rocks and minerals valuable? The quality of the specimen determines rocks, gems, and minerals’ value, how well cataloged they are, their rarity, as well as their history. Color, shape, transparency, size, density, weight, or structure are other factors that determine how much rocks are worth.

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