Spurrite Gemstone: Properties, Meanings, Value & More

Spurrite is a lesser-known collector’s gemstone beloved in grayish-purple hues. It joins the small family of purple gemstones and it’s most famous from Mexico.

Spurrite minerals are uncommon, but cut spurrite gemstones are pretty rare, extremely rare when faceted. Most cut spurrites are cabochons or beads rather than faceted gems, but the cabochons are gorgeous.

In fact, the Gemological Institute of America (GIA) has only analyzed spurrite on three instances — in 2001, 2004, and 2019 — and the specimens were beads, a piece of polished rough, and a cabochon.

Today, we’ll be breaking down everything you need to know about spurrite gemstones!

Pictured above: Purple spurrite specimen from Japan | Image credit: D. Nishio-Hamane, Flickr, CC-BY-SA-2.0

Introducing the Spurrite Stone

Spurrite is a rare semi-precious gemstone, with gemstones often cut from purple or grayish-purple material. The stone can also be white, colorless, blue, yellow, or gray.

Technically, “paraspurrite” is a synonym for spurrite, though it was originally thought to be a distinct mineral polymorphous with spurrite — more on that in the History section.

Also, “strombolite” is used by crystal healers for gem-quality, dark purple to blue spurrite stones from New Mexico, USA.

Spurrite Synthesis & Studies

Scientists have studied spurrite for various reasons.

One main reason is preventative: in the formation of Portland cement, spurrite can form as rings in rotary kiln walls. Here, spurrite is a contaminant, so avoiding its formation is important for proper cement production.

A major topic of study is what conditions cause spurrite to form during cement production.

In a 1989 study, simulations found that fluorine and chlorine can act as mineralizers (catalysts for spurrite to form) and Ca3SiO5 is the only reagent-grade reactant that makes spurrite form without a mineralizer.

The 2012 book Applied Mineralogy of Cement & Concrete reiterated that elements like chlorine will cause “sticky” unwanted minerals like spurrite to form during sintering or calcination, clogging the cement kiln, pre-heater, or calciner.

Another 1989 study found that differential thermal analysis (DTA), thermogravimetry (TG), and X-ray diffraction (XRD) work well to estimate the amount of spurrite in cement kilns.

Researchers have also created synthetic spurrite to research the conditions under which wollastonite and calcite convert to spurrite and carbon dioxide. This study, published in 1957, was the first reported synthesis of spurrite.

Pictured above: Rough spurrite specimen from Fuga Mine, Japan | Image credit: Trtrtr, Public domain

Spurrite Specifications & Characteristics

A calcium carbonate silicate, the formula for spurrite is Ca5(SiO4)2(CO3). Spurrite, tilleyite, and scawtite are the only known calcium carbonate silicate minerals.

Internally, spurrite has two layers: one layer has groups of [CaO8] polyhedra adjoining [CO3], while the other layer has [CaO2] polyhedra adjoining isolated [SiO4] tetrahedra.

Common impurities are titanium, aluminum, iron, manganese, magnesium, sodium, and potassium.

Spurrite is usually found as granular masses that are similar to crystallized marble in appearance. Less often, spurrite forms small, anhedral crystals (no distinct crystal faces) or stubby, prismatic crystals. Some spurrite crystals have been found in radial, bladed habits.

Spurrite crystals can also display two types of twinning: polysynthetic twinning (multiple twins aligned parallel) along {001} and {101}, plus simple twinning along composition planes {001} or {205}.

Spurrite Identification

Spurrite can be a bit tricky to identify but not impossible.

Two destructive methods (ideally used as a last resort) are with a blowpipe and weak hydrochloric acid.

• Under a blowpipe, spurrite has a strong calcium flame reaction, then becomes white and porcelain-like (losing vitreous luster).

• In weak hydrochloric acid, spurrite will effervesce (foam, hiss, and bubble), then dissolve, becoming fully gelatinous and/or leaving a white powdery residue.

The mineral’s luminescence can also be helpful but varies. Many spurrite specimens display green cathodoluminescence (fluorescence caused by electron bombardment, tested with luminoscope or scanning electron microscope), plus green SW-UV fluorescence.

However, some specimens studied have shown pale blue LW-UV fluorescence but no SW-UV fluorescence, while others had orange and pinkish-orange cathodoluminescence. These results could be influenced by other minerals in the aggregates studied, though.

Here are the spurrite properties listed:

• Mohs hardness: 5

• Color: Colorless, white, grayish-white, gray, grayish-purple, purple, purplish-blue, lavender, light blue, yellow

• Crystal structure: Monoclinic; Pseudo-orthorhombic

• Luster: Vitreous or resinous

• Transparency: Transparent to opaque

• Refractive index: 1.637-1.681

• Density: 3.01-3.02

• Cleavage: Perfect on {001}, distinct/good on [100], poor/indistinct on {100}; (001) ^ (100) = 79°

• Fracture: Uneven or splintery

• Streak: White

• Luminescence: Variable; Inert or green in SW-UV, light blue in LW-UV; Usually green (sometimes pinkish-orange or orange) cathodoluminescence

• Pleochroism: None reported

• Birefringence: 0.039-0.040

• Dispersion: Relatively weak, crossed/inclined

Pictured above: Necklace with spurrite, sugilite, and lepidolite | Image credit: Becky Haner, Flickr, CC-BY-SA-2.0

Spurrite History

The name “spurrite” honors Josiah Edward Spurr, an American economic geologist who found the first specimens in 1907. Spurr found these specimens in the Velardeña mining district in Mexico with American mining geologist & engineer George Henry Garrey.

This name was given by American optical scientist & geophysicist Fred Eugene Wright when he wrote the first description of the mineral in 1908. Spurr and Garrey sent Wright some thin sections of the mineral, and Wright’s analysis uncovered odd optical properties.

Upon finding this, Spurr had Garrey send him more rocks from the type locality. Two of the minerals in the second round of samples were new minerals — spurrite and hillebrandite — while the third was gehlenite. This was the first time gehlenite was found in North America.

In 1962, American geologist Alan A. Colville and American researcher Patricia A. Colville reported a new polymorph of spurrite. Norm Nichols discovered it in the Darwin mining district of Inyo County, California, USA, now a co-type locality for spurrite.

They named the mineral “paraspurrite” because it was closely related to spurrite crystallographically but differed in having a double unit cell in the c* direction.

The International Mineralogical Association (IMA) initially approved the mineral but discredited paraspurrite as a species distinct from spurrite in 2010.

Pictured above: "Strombolite" spurrite pendant | Image credit: Healcrystal

Spurrite Healing Properties

As a popularly purple healing stone, spurrite’s meaning reflects the powers of other purple gemstones: inciting passion, increasing spiritual awareness, and functioning as third eye chakra stones.

Physical Healing

According to crystal healers, spurrite stone benefits include treating issues related to:

• Vision

• Headaches

• Sinuses

• Hormone imbalance

• Blood pressure

• Sleep (e.g. nightmares, insomnia)

Emotional Healing

Emotionally, spurrite is believed to:

• Promote optimism, especially in difficult times

• Comfort you during stress

• Dispel negativity

Picture above: Yellow spurrite specimen from New Mexico, USA | Image credit: Dave Dyet, Public domain

Spurrite Gemstone Properties

Besides its rarity, spurrite’s value also depends on its color, cut, clarity/transparency, and carat weight.

Color

The most desirable colors for spurrite are shades of purple.

Many purple specimens are mottled, often with white calcite lines filling fractures or green intergrowth with vesuvianite.

Deeper purple hues are also more valuable, especially if they’re evenly colored.

Cut

Any cut spurrites are rare, but faceted spurrites are very rare, meaning higher value.

Typically, spurrite gems are cabochons, carvings, or beads.

Most often, spurrite for sale is rough (uncut), sometimes polished or tumbled.

Clarity & Transparency

Clarity describes the degree of visible inclusions in a gem, which can lower its transparency and value. Rare fully transparent spurrites can carry higher value, along with translucent spurrites.

The most common inclusion in spurrite is black magnetite crystals. Dark perovskite inclusions are also present in many Japanese violet spurrites.

Carat Weight & Size

Rough spurrite crystals and aggregates can be quite large, like the up-to-six-inch crystals from Mexico and 6-pound slabs from Japan, but cut gems are usually smaller.

The few faceted spurrites cut are all under 3 carats. Spurrite cabochons can be much larger, reaching 40+ carats.

Pictured above: Rough blue spurrite specimen | Image credit: D. Nishio-Hamane, Flickr, CC-BY-SA-2.0

Spurrite Formation & Sources

Spurrite forms as a secondary mineral.

The formation happens during high-temperature, low-pressure contact metamorphism between carbonate sedimentary rocks (usually limestone) meeting mafic magma. The rocks become metamorphic and some minerals inside transform into spurrite.

Mining Locations

The top sources for gem-quality spurrite material are Mexico and Japan.

Other sources of spurrite worth mentioning are:

• Israel

• New Zealand

• Russia

• Siberia

• Turkey

• UK (Ireland, Scotland)

• USA (California, Montana, New Mexico)

Pictured above: White crystal aggregates of kilchoanite in a matrix of purple spurrite; From Fuka Mine, Japan | Image credit: David Hospital, CC-BY-SA-4.0

Spurrite Price & Value

Faceted spurrite gemstones are hard to find, but the few available are around $30 per carat or around $75 total.

Spurrite cabochons, even in valuable purple or blue hues, are available for under $1 per carat or around $15 to $50 total.

Rough purple spurrite slabs are available for $30 to $60 each.

Average prices for spurrite jewelry are:

• Spurrite Rings: $60 to $120

• Spurrite Pendants: $50 to $160

• Spurrite Beaded Necklaces: Around $200

Tumbled spurrite stones are usually about $3 to $6 each.

Spurrite Care and Maintenance

Luckily, gemstone care for spurrite is fairly easy. Given its cleavage and mid-range hardness, we recommend protective settings on spurrite rings.

Clean spurrite with warm water, mild soap, and a soft toothbrush. Only wipe dry with a lint-free, microfiber cloth.

Store separately from other gems to avoid scratches.

Spur Positivity with Spurrite Stones!

It’s a shame that spurrite isn’t well-known. We personally love the stone’s rare purple coloring, intriguing formation, and positive healing properties!

If you love it as much as we do, why not get a spurrite stone or ring for yourself?

Buy spurrite and other stunning gemstones today!