Dickinsonite Gemstone: Properties, Meanings, Value & More

Dickinsonite is a soft, very rare mineral only known among seasoned collectors. The green to yellowish-green stone was originally discovered in Connecticut, USA. It’s partly known for its relationship to arrojadite minerals.

In terms of exact rarity, dickinsonite as a mineral is already rare. But you’ll hardly ever see dickinsonite as a cut gemstone, if ever at all.

If you love lesser-known minerals and gems, we’re with you. That’s why we’ve brought together our mineral expertise to bring you this comprehensive guide on all things dickinsonite, from its properties and benefits to its prices and geology.

Let’s jump in!

Pictured above: Dickinsonite specimen on display at Canada's Pacific Museum of Earth | Image credit: Pacific Museum of Earth, Flickr, CC-BY-SA-2.0

About Dickinsonite Stone

Dickinsonite is a very rare semi-precious gemstone found in shades of green, sometimes with yellow or brown undertones.

Technically, the name “dickinsonite” is unofficial — the official name approved by the International Mineralogical Association (IMA) is Dickinsonite-(KMnNa). For brevity’s sake, though, we’ll use “dickinsonite” in this article.

Scientists have made synthetic versions of similar minerals, like a synthetic Fe3+ arrojadite reported in 1986 or an yttrium phosphate with a fillowite-type structure reported in 2009. But with limited dickinsonite uses, no synthetic versions have been created yet.

Dickinsonite Specifications & Characteristics

Dickinsonite is a complex mineral with various formulas given. The formula approved by the IMA is K(NaMn)CaNa3AlMn13(PO4)12(OH)2, meaning it consists of potassium, sodium, manganese, calcium, aluminum, phosphate, and hydroxide.

The mineral belongs to the arrojadite group of basic phosphate minerals. Made up of 16 minerals, 13 have arrojadite root names. The others are fluorcarmoite-(BaNa) and sigismundite (briefly renamed arrojadite-(BaFe) until 2022).

Additionally, arrojadite-(KFe) is the iron endmember of a series with dickinsonite-(KMnNa), the manganese endmember.

In terms of habits, dickinsonite crystals may be tabular or pseudo-rhombohedral, typically with triangular striations. Often, the mineral occurs in foliated, micaceous, lamellar, radiated, curved, or stellated forms. It can also occur as disseminated scales.

Dickinsonite properties listed:

• Mohs hardness: 3.5-4

• Color: Oil green, olive green, grass green, yellowish-green, brownish-green

• Crystal structure: Monoclinic

• Luster: Vitreous (glassy); Pearly on cleavages

• Transparency: Translucent to transparent

• Refractive index: 1.648-1.671

• Density: 3.34-3.41

• Cleavage: Perfect and easy (almost micaceous) on {001}

• Fracture: Irregular/uneven

• Streak: Almost white

• Luminescence: None

• Pleochroism: Present; Light olive green to lighter olive green to very pale yellowish-green

• Birefringence: 0.013-0.014

• Dispersion: Moderate to strong

Pictured above: Portrait of Edward Salisbury Dana, the American mineralogist who first described dickinsonite, Yale College Class of 1870 | Image credit: Yale University Manuscripts & Archives Digital Images Database, Public domain

Dickinsonite History

American mineralogist & physicist Edward Salisbury Dana and American mineralogist & academic administrator George Jarvis Bush wrote the first description of dickinsonite based on specimens from Redding in Connecticut, USA.

The description was published in the American Journal of Science and Arts in 1878 with the title “On a new and remarkable mineral locality in Fairfield County, Connecticut; with a description of several new species occurring there.”

The exact source, now the type locality, was a granite pegmatite in Branchville Quarry (now Fillow Quarry).

Abijah N. Fillow opened the mine in 1876 to start mining for mica he could sell. Fillow only found a small amount of mica and closed the mine, but before doing so, he preserved many mineral specimens he’d found there. Fillow showed these specimens to Dana in 1877.

Local Reverend John William Dickinson also found a number of specimens that he sent to the researchers for analysis and identification.

From all the combined specimens, Dana and Brush identified three previously unknown minerals: eosphorite, triploidite, and of course, dickinsonite.

Brush and Dana described dickinsonite as “one of the most remarkable and novel of the species” analyzed.

They named dickinsonite after Reverend Dickinson, as his donated specimens were “of the greatest service to us in the study of the species” and they wanted to “express our great appreciation of his generosity.”

In 1890, Brush and Dana published another study comparing the original compositional analysis of dickinsonite to a new analysis. They proposed that dickinsonite was actually dimorphous with fillowite, a mineral they’d found nearby and described in 1879.

Discovery of Arrojadite

Brazilian geochemist Djalma Guimarães wrote the first description of arrojadite in 1925, naming it after Brazilian geologist Miguel Arrojado Lisbôa. He described it as a new wagnerite group mineral that was a phosphate of iron, manganese, and other base elements.

The samples of Guimarães were massive specimens found in Serro Branco, Brazil. In the 1927 American Mineralogist report on the new mineral, American geologist William Frederick Foshag noted that the specimens were likely the same as South Dakota specimens described by William Parker Headden.

In fact, another synonym for dickinsonite that honored Headden was “headdenite,” given by Swedish mineralogist Percy Dudgeon Quensel in 1937.

Yet another name for arrojadite was hühnerkobelite, chosen by American mineralogist Marie Louise Lindberg in 1950 after discovering the mineral in Hühnerkobel, Germany.

The original arrojadite discovered turned out to be arrojadite-(KFe), but this wouldn’t be established until 2005 after decades of studies showing dickinsonite and arrojadite’s relationship.

Mineral Group and Name Changes

American mineralogists Charles Palache, Harry Berman, and Clifford Frondel were the first to recognize dickinsonite as an isotype of arrojadite in the 7th edition of The System of Mineralogy of Dana published in 1951.

American mineralogist Daniel Jerome Fisher furthered the research using X-ray and powder methods for crystal and chemical comparison between the two minerals.

Fisher determined that dickinsonite and arrojadite form a series, with dickinsonite as the manganese (Mg2+-rich) endmember and arrojadite as the iron endmember, in 1965. He also argued that arrojadite should be named “ferroan dickinsonite,” though this wasn’t adopted.

In 1981, a group of scientists collaborated on a groundbreaking combined analysis of the arrojadite-dickinsonite series. These scientists were:

• American mineralogist Paul B. Moore,

• Japanese-American mineralogist Takaharu Araki,

• Italian crystallographer Stefano Merlino,

• Italian mineralogist Marcello Mellini, and

• Italian mineralogist Pier Francesco Zanazzi

Notably, they proposed the ideal arrojadite-dickinsonite series formula as KNa4Ca(Fe,Mn)2+14AL(OH)2(PO4)12.

Finally, French geologist Christian Chopin and Italian mineralogists Roberta Oberti & Fernando Cámara established the arrojadite group nomenclature in 2006. Each mineral’s root name is arrojadite if iron dominant or dickinsonite if manganese dominant, with multiple suffixes and prefixes when applicable.

In dickinsonite’s case, the new names were:

• Dickinsonite-(KMnNa)

• Dickinsonite-(KNaNa)

• Dickinsonite-(KNa)

• Dickinsonite-(NaNa)

Therefore, the mineral overall has the holotype name dickinsonite-(KMnNa), as approved by the IMA in 2005.

Pictured above: Arrojadite specimen from Dodium Plate Mine in South Dakota, USA | Image credit: Dave Dyet, Public domain

Dickinsonite Healing Properties

As a green healing stone, dickinsonite’s meaning reflects the hopeful and rejuvenating properties of other green gemstones.

Physical Healing

Physically, dickinsonite is believed to treat issues related to:

• Fatigue

• Immune system function

• Headaches / migraines

• Metabolism

• Digestion

Emotional Healing

Emotionally, dickinsonite uses recommended by crystal healers include:

• Encouraging unconditional love, both to oneself and others

• Promoting self-acceptance

• Increasing confidence

• Fostering personal and spiritual growth

• Manifesting happy, healthy relationships

• Diminishing anxiety and stress

Chakra Healing

Chakra stones can help open blocked energy centers (chakras) so energy can flow freely throughout the entire system. Dickinsonite is a chakra stone for the heart chakra, located below the breast bone.

The heart chakra governs acceptance of change and love in all its forms — familial, romantic, platonic, and self-love.

When the heart chakra is blocked, you might feel isolated, unworthy of love, or listless. Opening it with dickinsonite can help you embrace love, empathy, and the ups and downs of life.

Dickinsonite Gemstone Properties

Since it’s so rare as a gemstone, dickinsonite doesn’t have standardized grading factors. But we’ll still go over how these factors might apply to dickinsonite’s value:

• Color: All dickinsonite stones are some shade of green, but brighter or more pure green hues may be of higher value than stones with browner or more uneven coloring. Dickinsonite crystals with stronger pleochroism (where the color shifts under different viewing angles) may also be more valuable.

• Cut: Given the rarity of cuttable material, faceted dickinsonite gems are quite rare and valuable. The stone is almost always available for sale rough (uncut).

• Transparency: Dickinsonite crystals or gems with fewer visible inclusions and higher transparency may sell for higher prices than more translucent or heavily included stones.

• Carat Weight / Size: Both distinct crystals and cut gemstones are always small for dickinsonite. Faceted gems are always under 1-2 carats. Distinct crystals are also small.

Before they’re sold or even discovered, how does dickinsonite form in the first place?

Pictured above: Dickinsonite crystal on display with brazilianite and triphylite | Image credit: Aymée Meira, Flickr, CC-BY-SA-2.0

Dickinsonite Formation & Sources

Sources differ on whether dickinsonite is a primary or secondary mineral.

If you don’t know, primary minerals form inside rocks as the rocks themselves form; secondary minerals form when primary minerals undergo some type of alteration from forces like weathering, chemical changes, or hydrothermal activity.

What we do know is that dickinsonite definitely forms in granite pegmatites.

The primary mineral formation of dickinsonite would occur through hydrothermal processes in high-temperature (~800°C or 1472°F) granite pegmatites.

Secondary mineral formation would happen when primary phosphate minerals like triphylite or lithiophilite undergo changes from the granite pegmatites evolving.

According to Jerome Fisher’s 1965 article, dickinsonite will alter into alluaudite when heated in air to 500°C (932°F) or fillowite when heated in a vacuum to 850°C (1562°F).

As far as which stones are found near dickinsonite, commonly associated minerals are:

• Eosphorite

• Triploidite

• Lithiophilite

• Rhodochrosite

• Reddingite

• Fairfieldite

• Hureaulite

Minerals less often (but still sometimes) found with dickinsonite include:

• Quartz

• Fillowite

• Diadochite

• Purpurite

• Spodumene

Now that we know the geological side, where is dickinsonite found geographically?

Mining Locations

The only significant localities for dickinsonite are in Connecticut and Maine, USA. Faceted gems have only been cut from dickinsonite material from Connecticut.

The mineral has also been found in:

• Argentina

• Australia

• Canada

• Czech Republic

• Namibia

• Poland

• Rwanda

• USA (Arizona, New Hampshire, North Carolina, South Dakota)

Sources can somewhat affect dickinsonite’s price, as certain locales are known for higher-quality dickinsonite specimens that will fetch higher prices.

That said, let’s discuss what to expect when you start browsing dickinsonite for sale.

Pictured above: Plate of arrojadite-(KFe) crystals from Rapid Creek, Canada | Image credit: Rob Lavinsky, iRocks.com – CC-BY-SA-3.0

Dickinsonite Price & Value

Unfortunately, faceted dickinsonite is incredibly difficult — if not impossible — to come by at any price. At present, dickinsonite for sale is only available as rough specimens.

Luckily, these rough specimens come in a range of prices.

Small, massive or granular dickinsonite specimens are around $25 each. Larger massive specimens are $40 to $45. The priciest options are larger specimens with other rare minerals like triploidite and robertsite, which go for around $90.

Dickinsonite Care and Maintenance

Proper gemstone care is important for dickinsonite, given its softness and brittle tenacity. Always handle it carefully and store it away from other gemstones.

You can clean off dirt and grime with warm water and a soft toothbrush. Just keep dickinsonite away from acids, as it will dissolve in them.

Dazzled by Dickinsonite?

Dickinsonite may not be a household name, but this historic gem is a wonder. With lush green springtime hues, plenty of metaphysical benefits, and important geological history, dickinsonite is a must-have in any rare mineral collection.

Buy dickinsonite and other lesser-known gemstones today!