THE MAGIC OF MARBLE

Durable yet soft enough to be workable, marble occurs in both solid and patterned colors from snow-white to a rainbow of soft pastels. With its fine grain, marble takes a gleaming polish and can be worked in great detail.
Because marble occurs in massive formations, it can be quarried as blocks suitable for the largest sculptures and most ambitious architectural applications. To many sculptors, marble's most appealing quality is its slight translucency which imparts a subtle glow to the polished stone.
OUT OF LIMESTONE
For all its beauty, marble originates as drab limestone, a common sedimentary rock that forms through the accumulation of shells, coral and other organic materials. Limestone consists primarily of the calcareous carbonate minerals calcite (calcium carbonate) and/or dolomite (calcium magnesium carbonate).
Most limestone is dark-gray in color; higher grades containing more than 70 percent carbonates have lighter-gray colors. With its dull luster and poor polishing qualities, limestone is not a particularly attractive rock.
But because of its abundance and low cost, it is widely used for exterior building blocks. Its biggest use, however, is as the raw material for manufacturing portland cement.
When subjected to metamorphic heat and pressure, high-grade limestone undergoes a dramatic change. It first takes on a plastic consistency as its fine-grained, crystalline structure is destroyed and many of its impurities driven off. Then, with reduced heat and pressure, this plastic mass recrystallizes as marble with a substantially higher carbonate content and a structure of interlocked grains of translucent calcite and/ or dolomite.
THE MAGIC OF MARBLE
Diese Geschichte stammt aus der December 2022-Ausgabe von Rock&Gem Magazine.
Starten Sie Ihre 7-tägige kostenlose Testversion von Magzter GOLD, um auf Tausende kuratierte Premium-Storys sowie über 9.500 Zeitschriften und Zeitungen zuzugreifen.
Bereits Abonnent ? Anmelden
Diese Geschichte stammt aus der December 2022-Ausgabe von Rock&Gem Magazine.
Starten Sie Ihre 7-tägige kostenlose Testversion von Magzter GOLD, um auf Tausende kuratierte Premium-Storys sowie über 9.500 Zeitschriften und Zeitungen zuzugreifen.
Bereits Abonnent? Anmelden

Earth's Oldest Impact Crater Yet
Scientists estimate the age of Earth at 4.543 billion years.

To Create New Species, Raise High the Mountains
It seems like plain old common sense. Increase the complexity and diversity of topography and you'll increase biodiversity. But now we have strong data to support that hypothesis.

A Moon as Old as Earth? Almost!
Earth is estimated to be 4.543 billion years old, and it's believed our Moon was born from a violent collision between the newly formed Earth and another young Mars-sized protoplanet dubbed Theia not long thereafter. But how long was \"not long?\"

ROCK & GEM FIELD GUIDES
Emerald is the green variety of beryl, colored by trace amounts of chromium and sometimes also vanadium.

POLISH FLINT
Flint has often been used throughout history and is thought to be as old as 160 million years.
Pterosaurs Are Flying High!
Pterosaurs were remarkable flying reptiles soaring the skies above dinosaurs.

SUNSET PEAR
By day, Julia DeLo works as an engineer in the aerospace industry and by night, she pursues her passion for cutting gemstones, applying her analytical and mechanical skills to optimize and simplify designs.

The More Things Change, the More They Stay the Same
Eucalyptus trees have been bugged for 52 million years!

Not All Gold Is Created EQUAL
Understanding the Differences Between Colors & Alloys

HARDROCK GAMES
The Enduring Appeal of Mine-Drilling Contests