The Origins and Composition of Colorado Yule Marble

THE STORY OF COLORADO YULE MARBLE AT MARTINCOONEY.COM

The Origins and Composition of Colorado Yule Marble

Colorado Yule Marble may be found only in the Yule Creek Valley, three miles southeast of  the secluded Rocky Mountain town of Marble, Colorado, 9,300 feet above sea level. It was discovered in the spring of 1873 by geologist Sylvester Richardson. In the same year, an unknown person selected several samples of marble and took them to Denver, but for whatever reason, failed to generate much in the way of genuine (moneyed) interest.  The marble duly became lost again, only to be rediscovered under obscure circumstances 10 years later by George Yule.

Little did any of these marble pioneers know, or even I am sure dare to dream, that this far flung, obscure seam of gleaming white marble would captivate the nation just a few decades later as Colorado Yule Marble is chosen, against stiff opposition, for the ‘Building Stone of the Lincoln Memorial‘.

What cannot be disputed however was the supreme quality of the Sylvester Richardson/George Yule discovery, for unlike Vermont and Georgia marble, Colorado Yule was formed as a result of contact metamorphism.

Prior to Yule’s discovery, all commercial American marble deposits were formed via mountain range erosion on a purely regional scale, called Regional Metamorphosis, with the heat generated as oceanic and continental tectonic plates grind over and under one another.  Meaning that the transformation from limestone to marble, or metamorphosis, was attained by limestone being ‘baked’ and crushed via the friction created at relatively sedate temperatures when compared to marbles such as Yule that were forged via direct contact with magma, or Contact Metamorphosis.

And so, with average magma temperatures ranging from 1,300F to 2,900 Fahrenheit, it was these almost unimaginable conditions that were responsible for Yule’s superb quality, stunning beauty, and growing popularity.

By contrast to Yule, both Vermont and Georgia marble are the result of Regional Metamorphism. And what is known as Tennessee marble is not technically a marble, as it did not ‘metamorphose’ from limestone at all.

Whereas such was the incredible heat and pressure exerted by the molten-hot layer of magma upon the sliver of Leadville limestone we now call Yule marble, that the intrusions of hot granitic magma recrystallized it into the prized and valued ‘pure’ white marble it is today; 99.5 percent pure calcite in fact.

Not only is the purity of Yule quite renowned, but the dramatic nature of its trace amounts of non-calcite intrusions carry with them hints and hues of blue and green, orange, yellows galore that serve as mysterious highlights to Yule’s swirling clouds of bluey gray streaks.

The five grades of marble currently offered by the Yule Marble Quarry are named: Calacatta Lincoln, Calacatta Gold Extra, Calacatta Golden Classic, Statuario Colorado, and Aspen Grey.

The four main groups of intrusions / inclusions are:

Quartz, in the form of cooled granite – the signature blueish gray color;

Mica, often appearing as thin golden streaks;

Feldspar, crystallized from magma, and used widely in the glass and ceramics industries;

and Pyrite, with its metallic pale brass-yellow hue, often appearing as bone fide chunks of fool’s gold.

Please hover for names, and click to enlarge

Greens, blues and the odd yellow tints are often glimpsed courtesy of numerous other minor inclusions such as: Shene, Apatite, Rutile, Zircon, Sphalerite, Iron, and Manganese, which plays a crucial role in fashioning Yule marble’s famous, and incredibly rare, ‘gold’ veining.

And so, now you know… precisely what all of those beautiful hues, magnificent stripes and mysterious subtle shades are all about, and why my signature Hand Carved Marble Bowls may possibly have ONLY been carved from a rough block of Colorado Yule Marble.

We will know so much more about the character of these two magnificent marbles when I get my hands upon a suitable block of Carrara. Will the markings, hues and veining match, or even surpass that of Colorado Yule? Will a Carrara “Hand Carved Marble Bowl” even hold together through the vigorous and prolonged carving process ? With more and more prominent leaders within the marble industry increasingly speaking along the lines that Yule is  ‘ of the finest quality ever to be quarried ‘,  I am now beginning to think, maybe, perhaps not.

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The STORY of COLORADO YULE MARBLE at MARTINCOONEY.COM

The Origins, Composition and Discovery of Colorado Yule Marble

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