Gadolinite Gemstone: Properties, Meanings, Value & More

Gadolinite is a dark mineral known for containing rare-earth elements, notably yttrium and cerium, and being the first rare-earth mineral ever found. The stone’s color may be green to brownish-black, but it’s usually close to black.

Technically, “gadolinite” is a group of minerals, but the name may be used to refer to one of the gadolinite minerals in this group.

Is gadolinite rare? The mineral is only somewhat rare, but faceted gadolinite gemstones are incredibly rare, if you can find any faceted examples at all.

Eager to learn more? Come along as we explore gadolinite’s varieties, properties, history, prices, and more!

Pictured above: Faceted Gadolinite-(Y), 2.09 ct, from USA | Image credit: Kay Günther / G-Empire The World of Gems / http://www.g-empire.de/

About Gadolinite Stone

Gadolinite (pronounced GAD-uh-lin-eyet) is a very rare green to black semi-precious gemstone but a less rare mineral. The stone is sometimes called “ytterbite,” specifically for yttrium-bearing gadolinite, which was the first gadolinite discovered.

The term “gadolinite” is often used as a synonym for cerium-bearing gadolinite — gadolinite-(Ce) — and yttrium-bearing gadolinite — gadolinite-(Y).

Gadolinite Uses

Gadolinite’s most notable characteristic is containing rare-earth elements — 17 elements with important, niche uses. The mineral can contain both “light” and “heavy” rare earth elements, specifically cerium, lanthanum, neodymium, yttrium, and traces of gadolinium.

Although yttrium and neodymium primarily come from minerals like monazite and bastnaesite, gadolinite is a strong candidate for future sourcing.

Of the light rare-earth elements in gadolinite, neodymium has the most uses. The primary use is for making magnets (the strongest magnets known), which are vital in many small electronic devices (like phones), medical equipment, and electrical car parts.

Yttrium is an important element of:

• Stronger aluminum and magnesium alloys

• Phosphors used in LED lights & LCD screens (including historical cathode tubes in televisions)

• Electrodes

• Heat- and shock-resistant glass camera lenses

• Electrolytes

• Superconductors

• Some cancer treatments

• Metal-cutting lasers

• Microwave radar sensor filters

• Catalyst for making polyethylene plastic

• Electronic filters

That said, gadolinite has many other important mineral properties besides the rare-earth elements present.

Pictured above: Gadolinite-(Y) from Norway | Image credit: Leon Hupperichs, CC-BY-SA-3.0

Gadolinite Specifications & Characteristics

As a silicate composed of iron, beryllium, and rare-earth elements, the general gadolinite chemical formula is written as (Ce,La,Nd,Y)2Fe2+Be2Si2O10 or (Ce,La,Nd,Y)2FeBe2O2(SiO4)2. But each gadolinite mineral’s formula differs (more on that in the next section).

Notably, some gadolinites contain traces of uranium and/or thorium, radioactive elements that can make them metamict (altered properties & diminished crystal structure from radioactive decay over time).

There are three gadolinite groupings to know about. From largest to smallest: gadolinite supergroup (GSG), gadolinite group, and gadolinite subgroup.

The GSG includes arsenates, silicates, and phosphates. It’s divided into the gadolinite group and herderite group.

The gadolinite group has minerals with dominant Si4+, whereas the herderite group has dominant phosphorus and/or arsenic pentavalent ions.

From there, the gadolinite group is separated into the datolite subgroup and gadolinite subgroup. The datolite subgroup has dominant divalent cations, while the gadolinite subgroup has dominant trivalent cations.

Within the gadolinite subgroup, there are 10 minerals.

Three have the name “gadolinite-” followed by the dominant trivalent cation — either cerium (Ce), neodymium (Nd), or yttrium (Y). Gadolinite-Y also has an unnamed hydroxide analogue.

If we say “gadolinite minerals” in this guide, we’re referring to those in the gadolinite subgroup, particularly those with “gadolinite” in their name.

Gadolinite crystals can be prismatic, rough, and/or coarse. They’re commonly terminated. The minerals also occur as masses, aggregates, or anhedral (irregular shape, no crystal faces) grains.

Gadolinite mineral properties listed:

• Mohs hardness: 6.5-7 (all)

• Color: Black, greenish-black, brown (all); Sometimes olive-green (Nd); Olive-green, grass-green, or light yellow-green in thin sections (Ce or Y)

• Crystal structure: Monoclinic (all); Amorphous if metamict

• Luster: Vitreous (all); Sometimes greasy (Y); Sometimes adamantine or sub-adamantine (Nd)

• Transparency: Translucent (Ce); Opaque, very rarely transparent in thin fragments (Y); Transparent (Nd)

• Refractive index: Overall varies from 1.77-1.82 or over-the-limit; 1.78-1.81 (Ce & Nd); 1.77-1.82 (Y)

• Density: Overall varies from 4.0-4.86; 4.20 (metamict); 4.36-4.77 (Y); 4.86 (Nd); 4.20 (Ce)

• Cleavage: None

• Fracture: Conchoidal (all); Sometimes splintery (Y)

• Streak: Grayish-green or greenish-gray (Y & Ce); White (Nd)

• Luminescence: Metamict specimens - sometimes thermoluminescence resembling pyrognomic properties (rapid recrystallization that causes incandescence when heated)

• Pleochroism: None

• Birefringence: None (metamict); Varies from 0.01-0.05 (all); 0.030 (Ce & Nd); 0.050 (Y)

• Dispersion: Strong/distinct (Y & Nd); Unknown (Ce)

Pictured above: Gadolinite-(Y) crystals from Slobrekka mine. On display in Iceland municipality's mineral collection in Åkle (translated from Norwegian) | Image credit: Ronald Werner, CC-BY-SA-4.0

Types of Gadolinite

The formulas of gadolinite minerals in the gadolinite subgroup are listed below. Some may differ according to the International Mineralogical Association (IMA).

• Gadolinite-(Ce): Cerium-dominant; Formula Fe2+Be2Ce3+2(SiO4)2O2 or Ce2Fe2+Be2O2(SiO4)2 from IMA

• Gadolinite-(Nd): Neodymium-dominant; Formula Nd2Fe2+Be2O2(SiO4)2

• Gadolinite-(Y): Yttrium-dominant; Y2Fe2+Be2Si2O10 or Y2Fe2+Be2O2(SiO4)2 from IMA

Other minerals in the subgroup are:

• Calcybeborosilite-(Y)

• Hingganite-(Ce)

• Hinggadnite-(Nd)

• Hingganite-(Y)

• Hingganite-(Yb)

• Minasgeraisite-(Y)

• Unnamed (OH-analogue of Gadolinite-(Y))

All are monoclinic except for minasgeraisite-(Y).

Gadolinite History

Gadolinite is a mineral of many firsts, as the first rare-earth mineral ever discovered and the source of the first rare-earth compound discovered, yttrium.

Who discovered gadolinite? It was first discovered in 1787 by Carl Axel Arrhenius, a Swedish army lieutenant and amateur geologist, who found it in Ytterby, Sweden.

He gave it to Swedish-Finnish chemist Johan Gadolin for analysis. Gadolin published his analysis in 1794, announcing that the mineral was composed (at 38 percent) of an unknown oxide (called “earth” back then).

(German chemist Friedrich Wöhler first isolated yttrium in 1828.)

In 1797, Swedish chemist Anders Gustaf Ekeberg analyzed another sample with an even higher yttrium content. Ekeberg named the new element “yttria” and the stone “ytterbite.”

However, both chemists misnamed beryllium in the formula as aluminum because beryllium wasn’t discovered until 1798. Ekeberg made an updated analysis. In 1800, German chemist Martin Heinrich Klaproth also analyzed the mineral and renamed it “gadolinite” to honor Gadolin.

In 1880, Swiss chemist Jean Charles Galissard de Marignac discovered the element gadolinium while analyzing the spectroscopy of gadolinium and cerite. He named it “gadolinia” after gadolinite.

Discovery of Each Gadolinite

The first gadolinite was renamed gadolinite-(Y) by the IMA in 1987. This set the standard for naming each gadolinite variety discovered after:

• Gadolinite-(Ce): First discovered in Norway, 1978; Approved in 1987

• Gadolinite-(Nd): Reported in 2008 and 2010; Approved in 2016; First officially named for specimens from Sweden in 2018

On the metaphysical side, what are gadolinite’s healing benefits?

Pictured above: Large euhedral gadolinite crystal | Image credit: Rob Lavinsky, iRocks.com – CC-BY-SA-3.0

Gadolinite Healing Properties

As a commonly black healing stone, gadolinite’s meaning reflects the protective and grounding properties of other black gemstones. Green or black gadolinite crystals can be used as root or heart chakra stones.

Other purported gadolinite gemstone benefits include:

• Balancing emotions

• Promoting transformation, growth, and development

• Providing protection from negativity

• Treating chronic pain

• Facilitating spiritual enlightenment

Gadolinite Gemstone Properties

There aren’t gadolinite gemstone value grading criteria. We’ll still cover how the standard factors apply to gadolinite:

• Color: Many gadolinite specimens are black or near-black, but green gadolinites are more valuable.

• Cut: Any cut gadolinites are rare, especially faceted gems. However, cabochons can be cut from massive gadolinite material. Most gadolinite for sale is rough, and even then, attractive habits are rare.

• Transparency: Transparency is rare in gadolinites, commanding higher value.

• Carat Weight & Size: Any faceted gadolinites would be small, given how rarely it’s transparent. Masses have yielded cabochons weighing multiple pounds. The largest crystals come from Norway, up to 36 cm long, but most gadolinite crystals are 1-2 cm.

Pictured above: Black gadolinite-(Y) grain in pale feldspar from Norway; Field of view 2cm | Image credit: © Zbynek Burival / Mineralexpert.org / (CC-BY-SA-4.0)

Gadolinite Formation & Sources

Gadolinite is mostly found in pegmatites, specifically granite and syenite pegmatites.

It’s also found where basalt and monzonite contact each other.

Mining Locations

Where is gadolinite found? The best gadolinite crystals are found in Norway.

Other notable sources of gadolinite are:

• Australia

• Greenland

• Japan

• Russia

• Sweden

• Switzerland

• USA (Texas & Colorado)

Huge nodules (up to 60 lbs) have been found in Texas, USA.

Pictured above: Tom Udø (1972-2018) managed to prepare this crystal in a mine in Frikstad, Iveland. It was photographed mounted on the wall of a stand in Tom's exhibition. The lighting conditions were difficult, and the picture is far from optimal. (translated from Norwegian) | Image credit: Ronald Werner, CC-BY-SA-4.0

Gadolinite Price & Value

Faceted gadolinite gemstones for sale are usually gadolinite mixed with other minerals, often yttrofluorite. These cost around $20 to $30 per carat, or about $40 to $85 total.

Most gadolinite available is rough (uncut).

You’ll usually find rough gadolinite for around $30 to $75 each. The top specimens can reach $950.

Gadolinite Care and Maintenance

First and foremost, gadolinite — specifically gadolinite-(Y) and gadolinite-(Ce) — is often slightly radioactive because it can contain uranium and thorium. Plus, it has an additional low risk from the rare earth elements present.

As such, you should follow our tips on handling toxic and radioactive gems when handling or storing gadolinite.

In terms of gemstone care, gadolinite is soluble in acids, so keep it away from those. Store it in an enclosed container separately from other gems.

Gravitating Toward Gadolinite?

Gadolinite may not be the most beautiful stone, but there’s more than meets the eye. If you’re looking for a unique stone with rare elements and lots of history, gadolinite belongs in your collection!

Buy gadolinite gemstones today!