All about Black Basalt Stone

Basalt is an aphanitic extrusive igneous rock, which is used widely in construction industries. This article will compile information of what basalt is and all the facts about black basalt stone you should know, for those who are curious.

Table of Contents:

1. 1. What is Basalt?
2. 2. What is Black Basalt Stone made of?
3. 3. What does Black Basalt Stone look like?
4. 4. Black Basalt Stone Physical Properties
5. 5. How does Black Basalt form in nature?
6. 6. Where is Black Basalt Stone found?
7. 7. Is Black Basalt Stone easy to cut or drill?
8. 8. How much is Black Basalt Stone worth?
9. 9. What is Black Basalt Stone used for?

1. What is Basalt?

Basalt is an igneous rock that is formed through the cooling and solidification of lava. Igneous rocks are one of the three main types of rocks, along with sedimentary and metamorphic rocks. They are formed from the cooling and solidification of molten rock material, either magma (below the Earth's surface) or lava (on the Earth's surface).

In the case of basalt, it is specifically formed from the rapid cooling of lava. When molten lava erupts from a volcano and reaches the Earth's surface, it is exposed to the relatively cooler temperatures of the atmosphere or surrounding environment (like under the ocean). The rapid cooling of lava prevents large crystals from forming, giving basalt the formation of fine-grained crystals in the rock.

FAQs:

1. Is Black Basalt an intrusive or an extrusive rock?

Black Basalt is an extrusive igneous rock. It forms from the rapid cooling of lava at the Earth's surface, typically in volcanic environments.

2. What is the texture of Black Basalt Stone?

Black Basalt Stone typically has a fine-grained texture (also called aphanite). This means that the individual mineral grains in the rock are too small to be easily seen without the aid of a microscope.

3. What is Black Basalt formation?

Black Basalt is formed through the cooling and solidification of lava when in contact with air or water.

2. What is Black Basalt Stone made of?

The composition of black basalt stone plays a crucial role in determining its properties, including its color and various physical characteristics. Black Basalt is primarily composed of several minerals, and the relative proportions of these minerals contribute to the rock's overall appearance and properties.

Plagioclase Feldspar

This is one of the dominant minerals in basalt. It is a type of feldspar mineral that can range in color from white to gray. The specific type of plagioclase feldspar found in basalt is often a sodium-rich variety known as labradorite.

Pyroxene

Pyroxene minerals, such as augite, are common in basalt. Augite is a dark-colored mineral, typically black or dark green, which contributes to the overall dark coloration of basalt.

Olivine

Olivine is another mineral that can be present in basalt, giving it a greenish tint. However, olivine is not always present in significant amounts.

3. What does Black Basalt Stone look like?

Besides its fine-grained texture, we can tell if the rock is black basalt by its typical dark color, ranging from black to dark gray depending on its mineral composition.

The dark color is primarily due to the presence of minerals like augite (a type of pyroxene) and, to some extent, magnetite. These minerals contain dark-colored elements such as iron and magnesium, contributing to the overall coloration of the rock. The absence of light-colored minerals in significant amounts, combined with the fine-grained texture resulting from rapid cooling, prevents basalt from having a light or pastel color.

Black Basalt Stones found in nature

Over time, exposure to weathering processes can alter the color of basalt. The presence of iron-rich minerals, such as magnetite or hematite, in the basalt can lead to the development of brown or rust-colored stains that are found in black basalt in nature. This is often the result of oxidation, where iron minerals react with oxygen in the air or water. This feature also explains why basalt stone turns brown ultimately when exposed to damp conditions for a long time.

It's essential to note that the brown color in black basalt is often a result of secondary processes acting on the rock after its initial formation. Freshly erupted or unaltered basalt tends to exhibit the characteristic dark colors associated with its primary mineral composition, such as plagioclase feldspar and pyroxene.

4. Black Basalt Stone Physical Properties

Density

Black Basalt is generally a dense rock, and its density is influenced by the mineral composition. The presence of heavy minerals like magnetite and the overall compactness of the rock contributes to its high density. The density of Black Basalt is around 2.70 - 3.30 g/cm3 (which is 2.9 g/cm3 on average).

How heavy is Black Basalt? 

In terms of weight, black basalt is generally considered a dense and heavy rock due to its mineral composition. This density contributes to its durability and strength, making it a robust material for construction and infrastructure projects. The heavy nature of black basalt enhances its stability and resistance to various environmental conditions.

Hardness

Black Basalt is a relatively hard rock, scoring from 6 to 7 on the Mohs scale of mineral hardness – meaning it's harder than platinum or iron. Its hardness is determined by the minerals it contains, with minerals like plagioclase feldspar and pyroxene contributing to the overall hardness.

Porosity

Black Basalt is often less porous than some other types of rocks due to its fine-grained nature, which results from the rapid cooling process, commonly reaching 0.17%. However, porosity can vary depending on factors such as vesicles in the rock, which are small cavities formed by trapped gas bubbles during the rapid cooling of lava.

Is Black Basalt safe to use?

Black Basalt is non-toxic, making it environmentally friendly and safe for various uses. Unlike some materials that may release harmful substances, black basalt does not pose health risks when handled or used in construction. Additionally, black basalt is non-explosive, meaning it does not undergo explosive reactions or pose explosion hazards, making it a stable and secure material for construction and industrial purposes.

Black Basalt is also non-flammable, meaning it does not catch fire easily and does not contribute to the spread of flames. This property enhances its suitability for applications where fire safety is a priority, such as in the construction of fire-resistant structures or the manufacturing of fire-resistant textiles.

Heat resistance

Moreover, black basalt exhibits excellent heat resistance (up to 700 Celcius degrees), withstanding high temperatures without significant structural degradation. This heat resistance makes black basalt a preferred material for applications where exposure to elevated temperatures is common, such as kitchen countertops, and fireplace stone.

FAQs:

1. Can you scratch black basalt?

Black Basalt is generally a hard and durable rock. While it can be scratched by harder materials, it is not easily scratched by common objects. The hardness of black basalt varies, but in general, it is not considered a soft rock.

2. Is basalt hard to crush?

Black Basalt is known for its hardness and durability. It can be challenging to crush compared to some softer rocks. The exact difficulty of crushing basalt depends on factors such as the specific mineral composition and the size and shape of the grains. In industrial processes, basalt may require more energy to crush compared to softer rocks.

5. How does Black Basalt form in nature?

Black Basalt formations in nature can exhibit various shapes and structures, each influenced by the specific conditions under which the black basalt is formed. Here are a few notable types of black basalt formations

Columnar Basalt

Columnar basalt forms when thick lava flows cool and contract, leading to the development of hexagonal columns. These columns typically have a distinct geometric pattern and can range in size from a few inches to several feet in diameter. Columnar basalt is often the result of slow cooling, allowing the rock to contract and crack in a columnar pattern.

Pillow Basalt

Pillow basalt forms underwater when basaltic lava erupts beneath the ocean's surface. The rapid cooling of the lava due to contact with cold seawater results in the formation of rounded or pillow-shaped structures. Each "pillow" represents a single eruption event. This type of basalt is commonly found on the ocean floor at mid-ocean ridges.

Basaltic Lava Plateaus

Large-scale basalt formations can occur as lava plateaus or flood basalts. This type of basalt formation is associated with extensive volcanic activity where vast amounts of basaltic lava are effusively erupted over a broad area. As the lava spreads and cools, it forms expansive plateaus with relatively flat surfaces.

Basaltic Columns in Volcanic Necks

Basaltic columns can also form within volcanic necks, which are the solidified remnants of ancient volcanic conduits. Over time, the surrounding rock erodes, exposing the vertical columns that once filled the volcanic neck. The Giant's Causeway in Northern Ireland is a famous example of basaltic columns in a volcanic neck.

Basalt Dikes

Basalt dikes are vertical or near-vertical sheet-like intrusions of basalt that cut across existing rock formations. They form when molten basaltic magma is injected into fractures or cracks in the Earth's crust and then solidifies. Dikes can often be observed as dark, linear features in the landscape.

Basaltic Caves and Columns in Lava Tubes

Lava tubes are tunnels formed by the flow of lava. In some cases, the outer layer of the lava tube solidifies, while the molten lava continues to flow within. As the lava drains out, it leaves behind cave-like structures with basaltic columns. The Cave of the Winds in Colorado is an example of such a formation.

FAQs:

1. What types of black basalt formations can be found in Vietnam?

In Vietnam, black basalt formations can be columnar basalt or block-shaped basalt (which is shorter than columnar basalt), found in Central Highland and parts of the Southeast Region of Vietnam.

6. Where is Black Basalt Stone found?

Black Basalt is not considered a rare stone; in fact, it is one of the most common types of igneous rocks on Earth (on the Moon and Mars too!), and it also makes up a significant portion of the Earth's oceanic crust. It is often associated with volcanic activity and is found in various geological settings, including volcanic islands, mid-ocean ridges, and continental flood basalt provinces.

Therefore, Black Basalt is predominantly found in regions with a history of volcanic activity. Areas with active or extinct volcanoes are likely to have black basalt deposits. Some countries that have a significant amount of black basalt reserves are:

• Vietnam: Central Highland is a hot spot for Black Basalt in Vietnam, where the ancient geological activities enrich the landscape with basalt reserves and fertile soil. 
• Iceland: Known for its volcanic landscapes, Iceland has extensive basalt formations, making it a potential source of basalt.
• India: Certain regions in India, including the Deccan Traps, are characterized by extensive basalt flows.
• United States (Hawaii): Hawaii, being a volcanic archipelago, is home to basaltic lava flows. The islands are a notable source of basalt.
• Mexico: Volcanic regions in Mexico, such as the Trans-Mexican Volcanic Belt, contain basalt deposits.
• Italy: The volcanic activity in Italy, particularly around Mount Etna and Vesuvius, contributes to basalt formations.
• Saudi Arabia: The Arabian Peninsula has areas with basaltic rocks, including Saudi Arabia.

7. Is Black Basalt Stone easy to cut or drill?

Black Basalt is generally considered to be a hard and dense rock, which can make cutting and drilling more challenging compared to softer stones. The ease with which basalt can be cut and drilled depends on several factors, including its specific mineral composition, texture, and the tools and techniques used for the cutting or drilling.

In terms of cutting, black basalt can be worked with various tools such as saws, but the hardness of the rock may require specialized equipment with diamond-tipped blades or other abrasives. Cutting basalt may generate heat, so cooling methods (such as water) may be necessary to prevent excessive wear on the tools.

When it comes to drilling, black basalt can be drilled using conventional methods, but again, the hardness may require the use of diamond or tungsten carbide drill bits. The drilling process may be slower compared to drilling softer materials.

8. How much is Black Basalt Stone worth?

The cost of black basalt stone can vary widely depending on various factors such as its origin (which determines the logistic cost and the stone composition that affect its characteristic), quality, size, manufacturing process, and supplier policies. Black Basalt is commonly used for various applications, including construction, landscaping, and decorative purposes. Here are some general considerations regarding how much is black basalt stone worth:

• Type and Quality: Different types of basalt may have varying characteristics, and the quality of the stone can impact its price. High-quality, selective, well-processed basalt may be more expensive than lower-quality options.
• Origin: Black Basalt is found in various regions worldwide. However, the price can be different as some types of basalt (with specific composition and characteristics) may be preferable and higher in price than others, besides the logistic cost.
• Size and Shape: Larger or custom-cut pieces of black basalt may cost more than smaller or standard-sized ones. Additionally, the shape and finish of the stone (e.g., rough, cut, polished) can affect the price.
• Supplier and Location: Different suppliers may offer varying prices based on their price policies, and the geographic location of the supplier can affect transportation costs.

9. What is Black Basalt Stone used for?

Black Basalt is commonly used as a construction material, particularly in the form of crushed stone for road construction and concrete aggregates. Black Basalt is also utilized in the production of fiber-reinforced polymers (FRP), where it undergoes melting and extrusion to create basalt fibers. These fibers can be used in composites for various applications, including construction and automotive components.

Additionally, black basalt stones are widely employed as stone objects for both interior and exterior designs that incorporate natural stone. Black basalt stone finds applications in paving, walling, flooring, and other surfaces such as countertops, pool coping, wall capping, etc. Tables, seats, fountains, statues, and decorative blocks can also be crafted from black basalt, as well as other natural stone materials.