List of Black Rocks and Minerals

The mysterious beauty of black rocks and minerals can be fascinating. From their sparkly surfaces to their unique textures, black rocks and minerals have captivated the attention of many.

To come up with this list, I extensively researched the types of rocks and minerals available. I reviewed earth science articles, collected and analyzed some of these pieces, and even consulted with experts in the field.

I then narrowed my list to agate, garnet, obsidian, and coal, among other rocks and minerals. This list should give you a better understanding of the varying types of black rocks and minerals available worldwide.

 

Names of Black Minerals and Crystals

I’ve spent years digging for rocks and minerals in the lower 48 states plus attending the Tucson Gem and Mineral Show.  As my knowledge about rocks has accumulated, I’ve naturally come to appreciate certain gems and minerals.

Here’s my list of minerals and crystals that I find fascinating.  Of course, I could add quite a few more minerals to the list but I wanted to keep it short and allow you to go on your own journey to find your favorite black minerals.  Feel free to share your thoughts and if you have a rare or unique stone that should be added to the list then contact me directly.

 

 

Black Agate

Agate is a type of cryptocrystalline quartz with unique bands running throughout.  It’s often found in various colors, such as red, brown, grey, and occasionally black. Black agate is known for its glossy exterior with white banding patterns.

 

Properties:

• Constitutes silicon dioxide
• Mohs hardness: 6.5 – 7
• Specific gravity: 2.59 – 2.66

Uses:

• Making jewelry, cabochons, and carvings
• Sought after by rockhounds due to its rarity and uniqueness

 

 

Black Spinel

Spinel can occur in every color of the rainbow but black Spinel is not commercially available.  You’ll see this gemstone in rock and mineral shows as well as private collections.  It doesn’t have commercial use other than one-off pieces of jewelry and specimens.

 

Properties:

• Mohs hardness: 7.5 – 8
• Specific gravity: 3.6 – 4.1
• Vitreous luster
• Glassy texture
• Brittle tenacity

Uses:

• Making jewelry
• Sought after by specimen collectors

 

 

Black Sapphire (Corundum)

The gem varieties of corundum are Ruby and Sapphire which means they’re the same mineral but addressed with different names due to the difference in color.  Black Sapphires are fairly common but you won’t see them in jewelry.  You can find them at rock and mineral shows.

Occasionally, you’ll see higher-quality Black Sapphires in cabochons that display a 4 or 6-ray star.

 

Properties:

• Mohs hardness: 9
• Density: 4.02 g/cm3
• Adamantine to vitreous luster

 

Uses:

• Production of abrasives and jewelry
• Manufacture of machine parts

 

 

Coal

Coal is a black sedimentary rock composed of carbon and elements such as hydrogen, oxygen, and nitrogen. It’s an essential energy source, hence a valuable mineral if discovered in large quantities.  If you only have a single lump of coal then you really don’t have anything of value.

Black coal is formed by accumulated plant matter over millions of years and is the most abundant fossil fuel.

 

Properties:

• Metallic luster
• Mohs Hardness: 2.7 – 3
• 1.3 – 1.4 relative density
• Moisture (15%)
• Heat content (26 – 33 Mj/kg)
• Ash (5-40%)
• Volatile matter (20-35%)

 

Uses:

• Generation of electricity
• Production of steel and other metals
• Production of charcoal, fertilizers, and other products

 

 

Black Diamonds

Diamonds are usually found in kimberlite, volcanic pipes filled with igneous rock but can also be found in alluvial deposits, which are the result of eroded kimberlite.

Black diamonds became popular in the early 2000s when jewelry designers began incorporating them into earings, pendants, and rings.  This trend has become mainstream and you can find these solid black faceted stones in all types of jewelry.

 

Properties:

• Mohs Hardness: 10
• High melting point
• Adamantine luster
• Resists chemical corrosion

 

Uses:

• Production of jewelry and high-end watches
• Abrasives for cutting
• Industrial uses

 

 

Melanite

Melanite is part of the Andradite garnet family and derives its color from titanium.  In specimen form, you’ll notice the metallic luster and mirror-like polish on the crystal surfaces.

 

Properties:

• Mohs hardness: 7 – 8
• Vitreous luster
• Specific gravity: 3.6 – 4.1
• Refractive index: 1.7 – 1.9

 

Uses:

• Sought after by rock hounds and crystal collectors

 

Graphite

Graphite is a naturally occurring form of carbon and is formed when sedimentary rocks containing carbon are subjected to high temperatures and pressures. I’d suspect Graphite is the most common black mineral in the world. I’m not sure about abundance but there are quite a few pencils in this world which makes me believe Graphite is the king of the most common black mineral.

Graphite is the most stable form of carbon and one of the world’s most widely used minerals.

 

Properties:

• Mohs hardness: 1 – 2
• Sectile tenacity
• Specific gravity: 1.9 – 2.3

 

Uses:

• Used in pencils, lubricants, and paints
• Manufacture of steel and other metals

 

 

Hematite

Hematite is a black-metallic mineral composed of iron oxide and is often found in sedimentary, metamorphic, and igneous rocks.

Hematite is an important source of iron and can be found in various shapes and sizes depending on the mine location. Its unique properties make it a popular choice for industrial applications.

 

Properties:

• Metallic luster
• Mohs Hardness: 5.5 – 6.5
• Specific gravity: 5.26
• Density: 5.3

 

Uses:

• Production of jewelry
• Used as a pigment in paints, dyes, and cosmetics
• Polishing compound

 

 

Ilvaite

Ilvaite is a lesser know mineral composed of calcium iron silicate hydroxide and is often found with other minerals such as quartz, feldspar, and amphibole.  I’m not aware of any commercial uses but rock hounds do collect the crystal forms.  Due to its crystal structure, Ilvaite can be confused with black Schorl Tourmaline.

 

Properties:

• Mohs Hardness: 5.5 – 6
• Specific gravity: 3.8 – 4.1
• Prismatic crystal class
• Monoclinic crystal system

 

Uses:

• Sought after by crystal collectors and rock hounds

 

 

Nuummite

Nuummite is somewhat rare and was initially discovered in Greenland. It’s composed of two types of amphibole minerals, gedrite and anthophyllite. It’s best known for its shimmering iridescent colors and unique crystalline structure which makes it a popular choice among collectors.

 

Properties:

• Mohs Hardness: 5.5 – 6.0
• Glossy metallic luster
• Density: 2.8 – 3.5
• Refractive index: 1.6 – 1.7

 

Uses:

• Decorative stone in jewelry

 

 

Obsidian

Obsidian is a naturally occurring volcanic glass formed as an extrusive igneous rock when molten lava cools quickly. Silica is the main mineral in Obsidian and the most common color is black even though you can find yellow sheen, rainbow, snowflake, and mahogany.

 

Properties:

• Mohs Hardness: 5 – 5.5
• Specific gravity: 2.4
• Glassy texture
• Vitreous luster

 

Uses:

• Making jewelry and decorative carvings

 

Common and Rare Black Rocks and Minerals

Black rocks and crystals are an exciting and diverse group of minerals sought after by rock hounds, jewelry manufacturers, and commercial entities.   Whether you’re looking to add a unique piece of jewelry to your collection or a rare crystal to your specimen collection, black minerals are a must-have.