Properties of Stones and Crystals

Find out what the stone you bought from me does!

A-L     M-Z     Quartz     Hematite & Magnetite
Upper Peninsula Stones

Hematite is my favorite stone. On a recent trip to Michigan's Upper Penninsula, I realized that some of what I had collected that I thought was hematite was, in fact, magnetite. So I decided to research and figure out how to tell these two iron stones apart.

I have included direct quotes from some sources, to better explain from a geological viewpoint what these minerals actually are & how they are formed.

Hematite   Specular Hematite    Hematite, Manmade
Jaspilite, Banded iron formation          Slag
Magnetite    Taconite    Hematoid Quartz

Hematite FE2 O3
Iron with impurities
Hardness: 5-6
Streak: red to red-brown
Color: black, metallic grey, can oxidize to red
AKA: iron oxide, haematite,

Hematite is a form of iron, as anyone can tell who has lifted a piece of it. It rarely occures as pure iron, which is why it is not magnetized. Kidney ore, or botryoidal, is the most pure form. The specular hematite found in the UP has impurities, sometimes includes magnetite which is why people have the false impression it is magnetic (see my info on specular hematite below).

"Pure hematite has a composition of about 70% iron and 30% oxygen by weight. Like most natural materials, it is rarely found with that pure composition. This is particularly true of the sedimentary deposits where hematite forms by inorganic or biological precipitation in a body of water.
Minor clastic sedimentation can add clay minerals to the iron oxide. Episodic sedimentation can cause the deposit to have alternating bands of iron oxide and shale. Silica in the form of jasper, chert, or chalcedony can be added by chemical, clastic, or biological processes in small amounts or in significant episodes. These layered deposits of hematite and shale or hematite and silica have become known as the "banded iron formations" -- from geology.com

Hematite is unique in that it forms in a varity of shapes. I have been collecting it in all its forms, see pictures to the left. Most have seen it as botryoidal, those of us in Michigan have seen specular. When it occurs as plates it will form roses. There is also needle or pencil, irridescent, and actual crystals.

"Crystals occurs in thin plates, as well as bundles of small micaceous plates, and in thin splinters. Most commonly massive, mammilary, botryoidal, reniform, oolitic, stalactitic, and radiating. Scalenohedral and rhombohedral crystals occur, as well as tabular and groups of tabular crystals. Crystals are often striated. Dendritic and rosette forms are also found. May form as a pseudomorph after other minerals, especially as octahedral crystals of Magnetite." - geology.com

Sidenote: in geology, they describe the 'crystal habit' of stones. A crystal habit is an external shape displayed by an individual crystal, influenced by the atomic structure of the crystal growth. So in the above quote, 'crystal' does not mean a crystal like quartz.

Hematite is an iron ore. And is mined for that reason. But as it is not pure iron, it has other uses. The hematite we see most often is black or silver, but it can occur red in color. And when you crush the black or silver, the dust often is red. Hematite used to be called bloodstone, as when it was grinded or polished, the water would run red.

Uses of Hematite (Pigment) :
The name hematite is from the Greek word "haimatitis" which means "blood-red." That name stems from the color of hematite when it has been crushed to a fine powder. Primitive people discovered that hematite could be crushed and mixed with a liquid for use as a paint or cosmetic. Cave paintings, known as "pictographs," dating back to 40,000 years ago were created with hematite pigments.
Hematite continues to be one of the most important pigment minerals. It has been mined at many locations around the world and has been traded extensively as a red pigment. During the Renaissance when many painters began using oils and canvas, hematite was one of the most important pigments. Hematite color was opaque and permanent. It could be mixed with a white pigment to produce a variety of pink colors that were used to paint flesh.
It is a very dense and inexpensive material that is effective at stopping x-rays. For that reason it is used for radiation shielding around medical and scientific equipment. The low cost and high density of hematite and other iron ores also makes them useful as ballast for ships.
hematite is the material used to make polishing compounds known as "red rouge" and "jeweler's rouge." Red rouge is a hematite powder used to polish brass and other soft metals. It can be added to crushed corn cob media or crushed walnut shell media for tumble-polishing brass shell casings. Jeweler's rouge is a paste used on a soft cloth to polish gold and silver jewelry. -- geology.com

As stated above, it stops x-rays and radiation. This includes the electromagnetic field from cell phones, wi-fi, ect. I have pieces around my house to block the signal of the Smart Meters, and by my computer and wi-fi.

Hematite makes beautiful jewelry, although not all beads and pendants are formed from the stone. some are manmade to look like hematite, often including some hematite mixed with other materials. Try a streak test, rub it across an unglazed tile. If the streak has any red in it, then it is hematite.

So how was hematite formed and where is it found? Answers below.

Geologic Occurrence:
"Hematite is found as a primary mineral and as an alteration product in igneous, metamorphic, and sedimentary rocks. It can crystallize during the differentiation of a magma or precipitate from hydrothermal fluids moving through a rock mass. It can also form during contact metamorphism when hot magmas react with adjacent rocks.
The most important hematite deposits formed in sedimentary environments. About 2.4 billion years ago, Earth's oceans were rich in dissolved iron, but very little free oxygen was present in the water. Then a group of cyanobacteria became capable of photosynthesis. The bacteria used sunlight as an energy source to convert carbon dioxide and water into carbohydrates, oxygen, and water. This reaction released the first free oxygen into the ocean environment. The new oxygen immediately combined with the iron to form hematite, which sank to the bottom of the seafloor and became the rock units that we know today as the banded iron formations.
Soon, photosynthesis was occurring in many parts of Earth's oceans, and extensive hematite deposits were accumulating on the seafloor. This deposition continued for hundreds of millions of years - from about 2.4 to 1.8 million years ago. This allowed the formation of iron deposits hundreds to several thousand feet thick that are laterally persistent over hundreds to thousands of square miles. They comprise some of the largest rock formations in Earth's rock record.
Many of the sedimentary iron deposits contain both hematite and magnetite as well as other iron minerals. These are often in intimate association, and the ore is mined, crushed, and processed to recover both minerals. Historically, much of the hematite was not recovered and was sent to tailings piles. More efficient processing today allows more hematite to be recovered from the ore. The tailings can also be reprocessed to recover additional iron and reduce tailings volume." --Geology.com

"Locations:
Hematite has numerous good localities, and therefore only the finest will be mentioned. Large and thick crystals have been found in Minas Gerais, Brazil, particularly at Antonio Pereira, Congonhas de Campo, Jaguaracu, and Itabira. Lustrous plates with flat or tabular crystals come from Novo Horizonte and Brumado, Bahia, Brazil. Most of the tumbled, polished Hematite comes from Minas Gerais.

Cumberland, in Cumbria, England, is a major source of Hematite specimens, especially the Specularite variety, as well as much of the globular and stalactitic specimens. Another classic occurrence is Rio Marina, on the island of Elba, Italy. The Cavradi Gorge in Tujetsch, Grischun, Switzerland is well-known for its outstanding and unique lustrous tabular Hematite crystals.

Morocco has also been a recent producer of fine collectible Hematite, with special note on Nador in the Nador Province, where excellent crystals and clusters have been found. The Wessels Mine in Hotazel, in the Kalahari manganese fields of South Africa has produced outstanding lustrous crystals including the rare prismatic forms.

In the U.S., enormous Hematite deposits exists throughout the western area of Lake Superior, especially in the Menominee iron range, Iron Co., Michigan. "Iron Roses" occur in the Thomas Range in Utah, as well as in numerous localities in Arizona, namely Aztec Peak, Gila Co.; Bouse, Yuma Co.; and in the Buckskin Mountains in La Paz Co. A classic New York locality is Chub Lake, St. Lawrence Co". -- minerals.net

Specular Hematite FE2 O3
Iron with impurities
Streak: red to redish brown
Color: silver, shiny
AKA: micaceous hematite,

Specular hematite has a metallic luster and appears to be a rock composed of shiny mica flakes. Instead those flakes are hematite. Even though this hematite has a silver color, it still produces a reddish streak - which is a key to hematite's identification. Hardness testing on specular hematite is difficult because the specimens tend to crumble.

"Hematite is not magnetic and should not respond to a common magnet. However, many specimens of hematite contain enough magnetite that they are attracted to a common magnet. This can lead to an incorrect assumption that the specimen is magnetite or the weakly magnetic pyrrhotite. The investigator must check other properties to make a proper identification.
If the investigator checks the streak, a reddish streak will rule out identification as magnetite or pyrrhotite. Instead, if the specimen is magnetic and has a reddish streak, it is most likely a combination of hematite and magnetite." From geology.com

Most of the information on hematite applies to specular also, including how it formed and where it can be found.

Hematite, Manmade :

Products called "magnetic hematite" and "iridescent hematite" are often offered for sale in gift, tourist, novelty, and science shops and their websites. Most of the time these materials are not hematite but are man-made materials that do not even have the same chemical composition as hematite. Buy them if you like them but not because you think that you are getting a unique mineral specimen.

Sidenote: there is such a thing as iridescent hematite in nature, but you will only find the real thing sold as a raw mineral, not as a shiny polished bead or stone.

Magnetite FE3 O4
Purest iron
Hardness: 5-6
Streak: black
Color: black, grey, metalic
AKA: lodestone

Because they are both iron ore, hematite and magnetite look identical with one big difference: magnetisim. Magnetite is best known for its property of being strongly attracted to magnets. Some forms of magnetite from specific localities are in fact themselves magnets. Commonly known as Lodestone, this magnetic form of magnetite is the only mineral that is a natural magnet. Due to the magnetism of lodestone, small iron particles are often found clinging to its surfaces. (Some dealers may even intentionally place metallic filings on a lodestone to demonstrate its magnetism.)

"When the earth formed, the heavier metals, such as iron, were pulled by gravity into the planet's core, where the Earth's magnetic field is generated. The earliest compasses had pieces of magnetite.
Although magnetite contains a higher percentage of iron and is easier to process, hematite is the leading ore because it is more abundant and present in deposits in many parts of the world." --geology.com

Both hematite and magnetite are often found banded with other materials, such as chert or quartz. Some of the pieces I brought back from the UP are like this, a magnet will stick to only one band on the rock. I found out that this combination is called taconite, but sadly is being crusted so that the iron ore can be used.

"Most of the iron ore mined today is a banded sedimentary rock known as taconite that contains a mixture of magnetite, hematite, and chert. Once considered a waste material, taconite became an important ore after higher grade deposits were depleted. Today's commercial taconites contain 25 to 30% iron by weight.
At the mine site, the taconite ore is ground to a fine powder, and strong magnets are used to separate magnetically susceptible particles containing magnetite and hematite from the chert. The concentrate is then mixed with small amounts of limestone and clay, then rolled into small round pellets. These pellets are easy to handle and transport by ship, rail, or truck. They can be directly loaded into a blast furnace at a mill and be used to produce iron or steel." --Geology.com

"Uses:
The abrasive known as "emery" is a natural mixture of magnetite and corundum. Some synthetic emery is produced by mixing magnetite with aluminum oxide particles. The production of synthetic emery gives the manufacturer control over the particle size and the relative abundance of aluminum oxide and magnetite in the product. Some finely ground magnetite is also used as an abrasive in waterjet cutting. In the past few decades, synthetic abrasives have filled many of the applications where magnetite was previously used.
Small amounts of magnetite are also used as a toner in electrophotography, as a micronutrient in fertilizers, as a pigment in paints, and as an aggregate in high-density concrete". -geologyl.com

Jaspilite, Banded iron formation

Banded iron formation, also shortly known as BIF, is a major source of iron. BIF is a rock type made up of substituting silica- and iron-rich bands. BIF is economically among the most significant rock types as our society is largely dependent on iron, which is principally extracted from this rock. Photosynthetic organisms that were producing oxygen, but reacted with the iron dissolved in seawater to create iron oxide minerals on the ocean floor, ended creating banded iron formations.

Composition: Banded iron formation contains layers of iron oxides (essentially either hematite or magnetite) isolated by layers of chert (silica-stocked sedimentary rock). Each layer is generally narrow (millimeters to few centimeters). The rock has a characteristically banded appearance due to differently colored darker iron-rich and lighter silica layers. In some cases BIFs may consist of siderite (carbonate iron-carrying mineral) or pyrite (sulfide) instead of iron oxides and in place of chert the rock may consist of carbonaceous (rich in organic matter) shale. In the UP, there is BIF with chert which is a purpleish red, and what we call Jaspilite with the red jasper.

BIF is a chemogenic sedimentary rock (material thought to be chemically catapulted on the seafloor). Since old age BIFs usually have been metamorphosed to a different degree (particularly older types), but the rock has heavily retained its original appearance since its constituent minerals are reasonably stable at higher temperatures and pressures. These rocks can be defined as metasedimentary chemogenic rocks.

Types: BIFs formed in three episodes i.e. 3500-3000 Ma (millions of years ago), 2500-2000 Ma, and 1000-500 Ma. The BIFs from these three episodes are known as Algoma-, Superior- and Rapitan-types, respectively. In each case there were several simulations that resulted in their formation.

Algoma-type is the oldest (from the Archaean) and appears to be linked with volcanic arcs. They are majorly found in old greenstone belts. Iron-rich minerals are customarily magnetite. Algoma-type iron ore bodies are comparatively small, generally less than 100 meters in thickness and several kilometers in lateral extent. Algoma-type accumulations are mined in the Bjørnevatn (Norway), Abitibi greenstone belt (Ontario, Canada), Kostomuksha (Russian Karelia), etc.

Superior So far it is also one of the significant types of banded iron formations formed during the Paleoproterozoic (Superior-type). They formed on firm continental shelves. Superior-type accumulations are in vast dimensions (greater than 100 meters in thickness and over 100 km in lateral extent). A crucial iron-bearing phase is hematite, but magnetite also occurs. Iron mines where BIFs pertains to Superior-type include Lake Superior (Canada, USA), Labrador (Canada), Hamersley Basin (Australia), Kryvyi Rih (Ukraine), and Transvaal Basin (South Africa), Quadrilatero Ferrifero (Brazil), Singhbhum (India).

The ocean was also a profuse source of silica to form chert layers since the seawater is thought to have been saturated with silica (120 mg/l) during most of the Archaean-Proterozoic.

Rapitan This type is the least significant with respect to the volume of ore mined. Their genesis appears to be linked with glaciations, global ice age (Snowball Earth) and related environmental changes. Iron-bearing mineral in Rapitan-type accumulations is hematite1.The world ocean was almost completely overlaid ice and thus separated from the atmosphere. That reintroduced diminishing conditions in the water column same as those that existed before the oxygenation of the atmosphere. This near global anoxia in seawater is usually perceived to be the reason why BIFs reappeared as iron deposited in the water and were later accumulations when the ice age subsided and the ocean was oxygenated again.

Problem With Banding of BIFs: Another key issue is the banding of BIFs. These bands could display seasonal cycles as modern varves do. Or it could be some other major cyclical alteration in ocean water chemistry or biology. It appears possible that there was some form of biological mediation and the alterations in BIF composition display the cyclical changes in the numbers of organisms.

Fun Facts
You can spot a 2.1 billion year-old rock with BIF formation at the National Museum of Mineralogy and Geology, Dresden, Germany.

Approximately a 3-billion-year-old BIF from Canada reveals that the atmosphere and ocean once had no oxygen.

Various controversies exist over BIF origination, and many theories have been proposed.

Banded iron formations, although widely mined, remain mysterious in several ways.

Understanding of their genesis is largely obstructed by the fact that there are no modern analogues.

As per a theory, BIF formation has been distinguishably ascribed to volcanic activity; rhythmic accumulation from iron and silica solutions because of oxidation, seasonal variations; and precipitation from solution as an outcome of unique oxidation-reduction conditions.

All these terms (Algoma, Superior, Rapitan) implies localities in Canada, but they are used to classify BIFs worldwide.

Many stones and crystals get their red color from the presence of hematite. My personal favorite is iron quartz, or as I call it, hematized quartz.

I have found myself drawn to stones only to find out later that there is hematite present in it. I do not like orange, but an orange aventurine heart caught my eye. I looked up info on it and found out that it was hematite that gave it that color. I wear that heart almost daily. You can find red jasper in the UP, the color coming from hematite. And those beautiful Lake Superior agates...guess where their red color comes from? Yep, hematite.

The piece I found in the U.P.

See Quartz Properties page
for metaphysical properties

Hematoid Quartz
AKA Ferruginous Quartz, Iron Quartz, or Hemitized Quartz. Sometimes sold as Tangerine Quartz.
Found where there is the presence of iron oxides. Looks like dirty, stained, brownish rock crystal or a vibrant brick red or orange crystal. Can be opaque and dull, or clear with areas or veils of reddish coloring. Created with iron staining, color is sometimes on surface.

Strawberry quartz is similiar, but has inclusions instead of staining. The "dots" of red hematite resembles strawberry seeds, hence the name. Cherry quartz is man made

One of my favorites, there are some beautiful specimens found in the Lake Superior area.

Slag -- Blast Furnace or Iron
Slag glass is a by-product of the iron and steel smelting industries. It is created when the raw iron ores are melted down to create pure iron. Silicate powders and sand are often added to the molten metals to help pull out impurities, and the slag is then separated and poured off into slag dumps. After the impurities cool, the result is slag. The different impurities and the number of air bubbles lead to the color and opaqueness of the slag. These slags were often just dumped into the lakes (before there were any environmental laws).
Blast Furnace Slag is produced three ways:
1. Air-Cooled Slag - cooled under atmospheric conditions and accelerate by water sprays.
2. Expanded Slag - cooled with controlled quantities of water to produce a lightweight product.
3. Granulated Slag - chilled quickly to form a glassy granular product.

Uses: Slag is used as an aggregate in road base fill, concrete, asphalt, concrete blocks, cement production, rock wool insulation, commercial roofs, railroad ballast, glass production, agricultural lime and silica fertilizer.

The most collectible slag at the moment is Leland Blue. Many people collect it and make jewelry out of this smelting by-product. The cleaner blue and the larger it is, the better price it can fetch. Frankfort Green is also relatively well known, looking much like the green of a green wine bottle. It's common to find greys, browns, amethyst like purple and green slag glasses, and mixtures of these. It's just up to you and a jewelry maker to decide what it's worth.