Stibiotantalite Gemstone: Properties, Meanings, Value & More

Stibiotantalite is an uncommon but stunning earth-toned gemstone found in shades of yellow, orange, red, and brown. The gem is known for its brilliant sparkle thanks to its high dispersion and refractive index.

Despite its name, stibiotantalite is not in the same mineral group as the mineral tantalite. Other minerals in the same group as stibiotantalite also have the same suffix, like bismutotantalite.

But back to the wonderful gemstone of the hour, our Gem Rock Auctions experts have done the digging to bring you this comprehensive guide to stibiotantalite gemstone properties, history, prices, benefits, and more!

About Stibiotantalite Stone

Stibiotantalite is a rare semi-precious gemstone often found in shades of yellow, orange, or brown when faceted. At first glance, you might mistake stibiotantalite for sphalerite, but we’ll touch on their key differences later on.

In astrology, yellow stibiotantalite is beneficial to those born under Gemini while orange stibiotantalite benefits Leo signs.

Stibiotantalite hasn’t been used much industrially given its rarity, but scientists have studied it for geological research and created synthetic versions of the mineral. So far, synthetic stibiotantalite hasn’t reached the gemstone market.

Stibiotantalite Specifications & Characteristics

Stibiotantalite is an antimony tantalum oxide with the formula Sb3+TaO4, as approved by the International Mineralogical Association (IMA). Mineralogists may also write the formula as Sb(Ta,Nb)O4 for the common presence of niobium as an impurity.

Niobium is a common impurity because stibiotantalite forms a solid-solution series with the antimony niobium oxide mineral stibiocolumbite. When tantalum exceeds niobium, the mineral is stibiotantalite; when niobium exceeds tantalum, it’s stibiocolumbite.

Stibiocolumbite also joins stibiotantalite in the cervantite mineral group, alongside bismutocolumbite, bismutotantalite, clinocervantite, and of course cervantite.

Habit-wise, stibiotantalite crystals are usually prismatic and striated. Many exhibit polysynthetic twinning or irregular intergrowth. The mineral may also be massive in habit.

Below is a complete list of stibiotantalite properties:

• Mohs hardness: 5-5.5

• Color: Brown, yellowish-brown, yellow, yellowish-gray, reddish-yellow, reddish-brown, greenish-yellow, or greenish-brown

• Crystal structure: Orthorhombic

• Luster: Vitreous, adamantine, or resinous (may start adamantine then turn resinous after exposure)

• Transparency: Translucent to transparent (near opaque in heavily included specimens)

• Refractive index: 2.374-2.457

• Density: 5.98-7.34 (natural); 7.53 (synthetic)

• Cleavage: Distinct/Good on {001}, Indistinct on {100}

• Fracture: Subconchoidal

• Streak: Light yellow or yellowish-brown

• Luminescence: None

• Pleochroism: None

• Birefringence: 0.083-0.090

• Dispersion: 0.146 (Strong)

Pictured above: Faceted sphalerite gemstone

Stibiotantalite vs Similar Gemstones

Stibiotantalite may be confused for other gemstones, particularly sphalerite and tantalite. Let’s go over how you can distinguish each one from stibiotantalite.

Sphalerite vs Stibiotantalite

Sphalerite is a zinc sulfide mineral in the eponymous sphalerite mineral group. It shares stibiotantalite’s autumnal coloring but is more often brown than yellow or orange.

Other notable differences include:

• Hardness: Sphalerite is 3.5 to 4; stibiotantalite is 5 to 5.5.

• Crystal System: Sphalerite is cubic (isometric); stibiotantalite is orthorhombic.

• Density: Sphalerite is less dense at 3.90 to 4.20; stibiotantalite has a density of 5.98 to 7.34.

• Birefringence & Doubling: Sphalerite only shows strain-induced birefringence sometimes; stibiotantalite has a relatively high birefringence of 0.083 to 0.090, which often causes doubling in faceted stones.

• Luster: Sphalerite’s luster is generally closer to adamantine; stibiotantalite can be adamantine but is usually resinous or vitreous.

• Optic Character: Sphalerite is isotropic; stibiotantalite is anisotropic with a biaxial (+) optic character.

Faceted sphalerite gemstones are rare but more common than faceted stibiotantalite gems.

Pictured above: Faceted tantalite gemstone

Tantalite vs Stibiotantalite

Technically, “tantalite” is a group of minerals but it’s often used for three minerals: tantalite-(Mn) or manganotantalite, tantalite-(Fe) or ferrotantalite, and tantalite-(Mg) or magnesiotantalite. All three are tantalum oxides with different dominant elements — manganese, ferrous iron, and magnesium, respectively.

Though stibiotantalite also contains tantalum, it differs from tantalite in:

• Hardness: Magnesiotantalite is 5.5, manganotantalite is 6, and ferrotantalite is 6 to 6.5; stibiotantalite is softer at 5 to 5.5.

• Mineral Group: Tantalites are in the columbite group; stibiotantalite is in the cervantite group.

• Colors: Tantalites are usually dark brown to black; stibiotantalite is often pale or bright shades of yellow to orange

• Streak: Tantalites have red, brownish-red, or black streaks; stibiotantalite has a pale yellow to yellowish-brown streak.

• Birefringence: Ferrotantalite and manganotantalite have higher birefringence ranges (0.160-0.170 & 0.150-0.20, respectively); stibiotantalite’s birefringence is 0.083-0.090.

• Transparency: Tantalites are usually opaque; stibiotantalite is usually translucent to transparent.

Other Similar Stones

Other minerals similar to stibiotantalite are cassiterite and cinnabar. Both have high density and high dispersion, like stibiotantalite. However, they differ from stibiotantalite in hardness — cinnabar is softer at 2 to 2.5 while cassiterite is harder at 6 to 7 — and density — cinnabar is heavier at 8.10 to 8.18 while cassiterite is closer to stibiotantalite at 6.98 to 7.01. Lastly, cassiterite’s refractive indices are 2.006 to 2.101, higher than that of stibiotantalite.

Pictured above: Photograph of Blackwood Road in Greenbushes, Western Australia, taken in 1920s | Image credit: Ernest Lund Mitchell, State Library of Western Australia, Public domain

Stibiotantalite History

Australian Government Assayer George Arthur Goyder wrote the first description of stibiotantalite in 1893. Son of the Goyder’s Line namesake, Surveyor General of South Australia George Woodroffe Goyder, George Arthur followed a similar path; his most notable work is The Prospector's Pocketbook published in 1888.

George Arthur Goyder was also an Assay Instructor at the School of Mines in Adelaide, which is how he came upon stibiotantalite.

In his description, Goyder describes how A. Knox Brown gave a sample of rinsed tin ore to the School of Mines and Industries Registrar J.J. East. The sample had come from the Greenbushes Tinfield in Western Australia — the same type locality as holtite.

East noticed that a portion of the sample that locals had called “resin tin” or “pale tin” actually contained antimony. However, its properties didn’t match any other known antimony minerals of the time.

So, East gave the waterworn, pebble-shaped sample to Goyder for analysis. After analyzing it, Goyder described the mineral’s composition as “essentially [a] tantalate of antimony, part of the tantalic acid being replaced by niobic acid, and part of the antimony by bismuth.”

Goyder proposed the name “stibiotantalite” in reference to the mineral’s primary components of tantalic acid — “tantalite” — and antimony — “stibio” for the historical Latin name of antimony, stibium.

Synthesizing Stibiotantalite

R.S. Roth and J.L. Waring of the US National Bureau of Standards (now called National Institute of Standards and Technology or NIST) published the first successful synthesis of stibiotantalite in 1963.

In their paper, Roth and Waring point out that stibiotantalite has the same (or similar) structure to other minerals like bismutotantalite (BiTaO4) and cervantite (SbSbO4).

They used this information along with lessons from previous attempts — namely experiments by Klas Dihlström in 1938 and Karin Aurivillius in 1951 — to synthesize minerals with a stibiotantalite structure type like bismutocolumbite and bismutotantalite.

Roth and Waring successfully synthesized stibiotantalite (along with bismutotantalite, stibiocolumbite, and pucherite) by calcining then heating single-phase specimens in sealed platinum tubes.

Pictured above: Stibiotantalite crystal from Afghanistan

Stibiotantalite Meaning & Healing Properties

Like many predominantly yellow gemstones, stibiotantalite’s spiritual meaning is one of happiness, hope, and healing.

Physical Healing

Crystal healers recommend stibiotantalite for treating physical ailments related to:

• Digestion

• Cramps

• Fatigue

• Skin problems

• Blood pressure

• Immune system function

Emotional Healing

Mentally, stibiotantalite is said to lower stress, increase energy, boost emotional resilience, encourage personal growth, and foster greater self-confidence.

Chakra Healing

Energy healers use chakra stones to balance one or more energy center (chakra), resolving the negative symptoms associated with an energy blockage. Stibiotantalite is a chakra stone for the solar plexus chakra.

Located in the upper abdomen, the solar plexus governs purpose and identity. Opening the solar plexus chakra with a stone like stibiotantalite can dispel feelings of detachment or insecurity, replacing them with greater self-respect and ambition.

Pictured above: Brownish-yellow faceted stibiotantalite gemstone

Stibiotantalite Gemstone Properties

Beyond the rarity of facetable material, stibiotantalite’s value as a gemstone also depends on its color, cut, clarity, and carat weight.

Color

Generally, the most valuable stibiotantalite color is vibrant yellow with little to no undertone. Color-zoning is common, so stones without color zones are sought-after.

Pale yellow stibiotantalite is also pretty valuable. Dark brown gems are usually least valuable color-wise, though their clarity, transparency, and size may change that.

Cut

Facetable material is somewhat rare, making faceted stibiotantalite gems the most valuable form. Common faceted cuts for stibiotantalite gemstones include cushion, rectangular, trillion, and oval shapes.

You can also find rough (uncut) stibiotantalite for sale.

Clarity & Transparency

Clarity, the degree of visible inclusions, can affect a gem’s transparency and quality. Most stibiotantalites are heavily included, but some slightly included to eye-clean gems (with no inclusions visible to the naked eye) are available at higher prices.

Typically, stibiotantalites will have fluid or solid inclusions like simpsonite or microlite.

Sometimes, stibiotantalite is found as an inclusion in other stones like goshenite or topaz.

Carat Weight & Size

Gem-quality stibiotantalite crystals are quite rare and the portions that are facetable are usually small. All faceted stibiotantalite gemstones are under 10 carats. Most are around 3 to 4 carats, with some up to 6 or 7 carats.

Image option 1: https://commons.wikimedia.org/wiki/File:Stibiotantalite-sd334a.jpg

Image option 2 of stibiotantalite on tourmaline: https://commons.wikimedia.org/wiki/File:Stibiotantalite-ck95c.jpg

Pictured above: Orange-red gemmy stibiotantalite crystals from San Diego County, California, USA; William Larson Collection | Image credit: Rob Lavinsky, iRocks.com – CC-BY-SA-3.0

Stibiotantalite Formation & Sources

Stibiotantalite is a pegmatite mineral, specifically complex granite pegmatites. The mineral forms when magma carrying fluid that contains dissolved tantalum and antimony slowly hardens, allowing the compounds to settle into pockets and crevices where they eventually crystallize as the magma turns to pegmatite.

Minerals often found associated with stibiotantalite include:

• Monazite

• Simpsonite

• Elbaite Tourmaline

• Holtite

• Antimony

• Tantalite

• Allemontite

• Stibiomicrolite

• Microlite

• Microcline

• Lithiophilite

• Cassiterite

• Columbite

Mining Locations

Most facetable stibiotantalite material historically has come from Mozambique, but the deposits are largely used up now. High-quality facetable stibiotantalite crystals are best known from Brazil and California (USA).

More sources of gemmy stibiotantalite material include:

• Australia

• Afghanistan

• Maine (USA)

• Myanmar

• Pakistan

• Russia

• Sri Lanka

• Sweden

• Zimbabwe

Pictured above: Yellow faceted stibiotantalite gemstone with thread-like inclusions

Stibiotantalite Price & Value

Despite its rarity, it’s not impossible to find faceted stibiotantalite gemstones for sale. However, they can be costly.

Overall, stibiotantalite price ranges for faceted gems go from about $100 to over $7,300 per carat or $25 to $2,250 total — many are under 1 carat, so their price-per-carat is higher than their total cost.

Rough stibiotantalite prices also vary based on quality factors like color, transparency, and size. The priciest options are large, well-formed, translucent to transparent yellow crystals. These typically start around $200 and can reach $1,600 each.

Smaller but still high-quality stibiotantalite crystals for sale are usually about $75 to $200. Unattractive or small, very cloudy brown specimens may go for $30 to $50.

Stibiotantalite Care and Maintenance

First off, it’s important to know that stibiotantalite does have a toxicity risk given the antimony, tantalum, and often niobium present. Finished gems are fine to handle but always wear protective gear when cutting or polishing the stone.

For gemstone care, stibiotantalite has mid-range hardness and often many inclusions. These factors make it more vulnerable to scratches and breaks. To avoid damage, avoid mechanical systems (e.g. ultrasonic) and stick to warm water, mild soap, and a soft toothbrush for cleaning.

Store stibiotantalite away from other gems, don’t wear the gem every day, and opt for protective settings for stibiotantalite jewelry.

Frequently Asked Questions

What is the hardness of stibiotantalite?

Stibiotantalite ranks at 5 to 5.5 on the Mohs mineral hardness scale, the same as titanite and monazite.

What is the meaning of stibiotantalite?

Etymology-wise, “stibiotantalite” has two parts: 1) stibio, derived from the Latin term and historical name for antimony stibium, and 2) “tantalite” for tantalum, both essential elements in the mineral’s composition. Spiritually, stibiotantalite symbolizes transformation, growth, and eternal bonds.

What are stibiotantalite’s properties?

The most notable properties of stibiotantalite are high density (up to 7.53 in synthetic material), high refractive indices (2.374-2.457), and high dispersion (0.146). This means stibiotantalite gems are heavy for their size with lots of brilliance (white reflected light) and fire (colorful reflected light).

What is stibiotantalite used for?

Stibiotantalite is primarily used as a gemstone for jewelry or collecting. Similar minerals like columbite and tantalite are important sources of tantalum, which is used in applications like electronics, surgical implants, superalloys, explosives, and metallurgy.

Step Into the World of Stibiotantalite!

Stibiotantalite is a rare, unique gemstone with sparkle and colors that will instantly boost your mood. This gem comes with rich history, fascinating elements, and alluring rarity that makes it a great find for anyone seeking a fresh, one-of-a-kind yellow gemstone.

Browse stibiotantalite for sale today!

Stibiotantalite