This mysterious mineral has defied scientists for years.
Not only does its crystal structure not abide by Huay’s Law of Rational Indices, but the way it forms is still not fully understood.
Despite the limits of our current knowledge of Calaverite, this article will go over everything you could think to ask about its formations, origins, uses, meanings, and value.
How to Identify Calaverite
When it comes to identifying Calaverite in the wild, it can be easily confused with other minerals.
Not only has it confused gold miners in the past (or gets confused with rocks that contain gold), but collectors all over the internet gather around specimens to analyze the crystal formation for correct identification.
Though it can be elusive, it does have some distinctive attributes that set it apart.
What Does Calaverite Look Like?
The shiny, long pillars of a Calaverite specimen often have people wondering, “Is Calverite a crystal?” or “Is Calaverite quartz?”
The simple answer is that Calaverite is a mineral that grows crystals similar to quartz.
It will have these distinctive features:
- The colors range from silvery white to brassy yellow
- Streaks ranging from greenish to yellowish-gray
- Opaque coloration
- Brittle and not very hard, with a 2 ½ to 3 on the Mohs scale.
- Fairly reflective and metallic
- Unequal crystal lengths with no cleavage
- 9.1-9.4 specific gravity
Calaverite can come in a few forms.
While it may form distinct crystals occasionally, it mostly forms crystals that lie flat against the stone.
It may also form blade-like or dustings of gold mixed with the charcoal gray of tellurium.
How Does Calaverite Form?
Though work is still being done to understand how Calaverite forms, scientists have a basic understanding of its transformation.
Calaverite is a telluride of gold (a compound between gold and tellurium), meaning that under hydrothermal conditions (heated water in the earth’s crust) minerals are oxidized and dissolved and gold or silver filaments replace them.
The resulting filaments form the crystals on the mineral’s surface with lengthwise striations throughout.
It is believed that Calaverite was originally deposited into the earth’s crust by relatively low-heated water ascending to the earth’s surface.
Commonly Confused Crystals or Minerals
The sometimes silvery crystals on Calaverite’s surface had Western Australia gold rush hopefuls in the 1890s confuse it with fool’s gold.
Calaverite is also a close relative of similar minerals, krennerite, and sylvanite, which also form gold-silver telluride.
You can tell the difference between Calaverite and fool’s gold much like you’d distinguish fool’s gold from gold nuggets.
Fool’s gold, or pyrite, forms into distinct cubes, or 8 or 12 faced structures with parallel striations.
The gold mineral, which is also present in Calaverite, rarely forms such a distinct structure.
Calaverite is also quite brittle, so the knife test should be the deciding factor.
Try to shave some of the crystal off.
Calaverite will dust or flake, and Pyrite will not.
Pyrite also creates a sulfurous smell when rubbed with a hard object.
Krennerite, while a close relative of Calaverite, is quite easy to distinguish.
Its crystals form rectangular prisms due to its orthorhombic lattices.
Sylvanite rarely forms distinct crystals, instead forming bladed or granular silver telluride.
Where can I find Calaverite?
Before taking a journey to find this elusive mineral (or attempt to), it’s important to understand its history and where it came from.
The first known discovery of Calaverite was in 1861 in the Stanislaus Mine in Calaveras, California, from which it took its name in 1868.
Across the world in Kalgoorlie, Australia, Calaverite was discovered in Golden Mile Deposits in 1896.
Miners believed it to be fool’s gold and subsequently threw it out.
They paved the streets with it, not understanding its full value until years later, causing a new gold rush to excavate the gold from the streets.
Those looking to score Calaverite for themselves would be hard-pressed to find any very easily.
It’s a very rare mineral only found in certain parts of the world where conditions are right.
A few of these locations include Kalgoorlie, Australia; Cripple Creek, Colorado; Nagyag, Romania; Quebec, Canada; and Calaveras County, California.
What Is Calaverite Used For?
The primary use for Calaverite has been to strip it of its gold components.
As a gold telluride, its composition of gold is fairly dense, sometimes over 42%.
Gold in this form is the second greatest natural source of gold in the world, and Cripple Creek’s mine is evidence of that; its discovery of Calverite in Colorado was its single greatest gold discovery in terms of raw quantity.
While Australia’s fool’s gold faux pas is funny, it does point to the construction capabilities of Calaverite.
If one were also to consider tellurium, the other rare compound in gold telluride like Calaverite, it may have yet more uses.
Tellurium itself is highly conductive and stores energy well.
Tellurium is also used to strengthen metals, improve their machinability, harden rubber, tint glass and ceramics, and as a material in solar panels, rewritable CDs, and as a catalyst in refining oil.
While Calaverite could be a beautiful collection piece, it would be an expensive one.
The rarity of the mineral makes it a museum piece.
If a collector were to find Calaverite on their own, they’d be quite lucky.
In terms of spiritualism, some believe Calaverite can be used to help one reflect on love in themselves and the universe; however, those who subscribe to the healing or magical power of crystals stray away from Calaverite in elixirs as tellurium is quite toxic.
How Much Is Calaverite Worth?
Standard market prices may vary between about $8 and $16 dollars per gram, but at auction, Calaverite can be worth hundreds, if not thousands of dollars.
Jewelry and other cosmetic or accessory materials made with Calaverite are also quite expensive, running into hundreds of dollars for a polished bit of the mineral with gold telluride exposed.
Calaverite is a mineral still baffling scientists and frustrating collectors around the world.
Its relatively recent discovery and ongoing experiments may soon tell us about its law-defying crystals, the unlikely pairing of gold and tellurium, and how it may yet be used for its conductivity and energy-storing capacity.
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