SOME HISTORICAL FACTS ABOUT MARBLE FORMATION THAT ARE BOUND TO LEAVE YOU FASCINATED ABOUT THIS STONE:
Do you love natural stone? Fans of natural stone countertops, tiles, fireplaces, walls, and building stone are natural allies to geologists. We all share a similar zeal for a glimmer of garnet and the sparkle of marble. The two disciplines have different ways of organizing and thinking about stone, which makes sense because we’re interested in different things. Geologists study rocks to learn more about what happened in Earth’s past. Regular people appreciate rocks because they’re useful, practical, and beautiful. Nonetheless, a bit of geology can shed light on why or where we’d want to use a given stone. Geology also helps us appreciate that every slab of stone offers a little glimpse into deep time and the dramatic forces that shape the planet.
This article touches on 13 different types of natural stone, with links to each type to explore further.
I’ll admit that geologic categories aren’t all that helpful for the way natural stones are used. Instead, we can group stones by the properties that matter to us, like how they hold up in the places we use them. Here’s an overview of rock types sorted by hardness and their ability to withstand an onslaught of marinara sauce.
RESISTANCE TO ACIDS:
When we talk about acid resistance, we’re referring to things like vinegar or citrus. Strong acids like oven cleaner and some bathroom cleaners will damage almost any stone, so keep those away from your stone, or better yet, use less toxic means to clean your home.
EARTH’S HISTORY AND HOW IT AFFECTED THE STONES WE SEE TODAY:
In the world of geology, all stones are related to each other. Over deep spans of time, any rock can turn into a whole new rock if it gets melted, squeezed, uplifted, or eroded. In fact, that’s exactly what’s been happening all through Earth’s history. Understanding the relationships between different stones can make it easier to see why some share similar traits. It also helps you appreciate the events that gave rise to all those beautiful slabs in the showrooms.
– Limestone forms in shallow, warm oceans and coral-rich beaches. It’s made of shells, shell fragments, and dissolved shells. Limestone can get buried and heated to taffy-like consistency, wherein it turns to marble. Both stones are made of the same mineral – calcite – but in marble’s case the calcite grains have been crystallized together, making the stone less porous. Marble’s distinctive grey streaks are clay layers from the original limestone that got heated and swirled.
– The relationship between sandstone and quartzite follows a similar theme. Sand grains gather on beaches, sand dunes, and riverbanks. Layers of sand get buried and pressed together, forming sandstone. If sandstone gets shoved down deep and compressed even further, the sand grains fuse together to become quartzite. As described in the Deep Dive into Quartzite article, this process is a gradual one. This means there are many gradations of sandstone and quartzite, ranging from highly porous sandstone to bombproof crystalline quartzite. The more deeply a stone is buried, the more tightly compacted it will get. The porosity of a stone translates into its ability to shrug off stains, and this is something that buyers can evaluate as they shop for different stones.
– Bluestone is a variety of sandstone. It formed as rivers flowed off a former mountain range along the eastern seaboard. As 400,000,000 year-old rivers wound their way through the landscape, they left behind pockets of sandstone in Pennsylvania and southern New York. Because the sandy deposits occurred in small, scattered areas, the quarries were small, too, setting the stage for generations of family-run quarrying operations throughout the region.
– Slate rocks show what happens if you crank up the thermostat on a stone. The predecessor to this stone is shale, which is compressed clay and is decidedly un-sexy. But add a little heat and pressure and those unremarkable clay particles start to grow and strengthen and the rock turns into slate. Unlike shale, slate is durable – and is workable into tiles, shingles, and of course, old-school blackboards.
– Adding even more heat and pressure will make the stone separate into bands of light and dark minerals. Striped or banded patterns are the hallmark of gneiss. The patterns can be calm or bold, straight or swirled. For commercial purposes, gneiss is usually classified as granite, because it’s made of the same minerals, and shares similar properties and colors.
– If the stone gets hotter still, it will start to melt. In some slabs of gneiss you can see melted blobs of quartz, showing the stone was right on the edge of becoming liquid again. If the whole thing melts, then you’ll end up with granite, an igneous rock.
WHAT BRINGS COLOUR TO GRANITE:
Granite means many things. It’s a catch-all category that’s often used to describe any hard, crystalline stone. In geology, granite is one specific thing: an igneous rock that is coarse-grained and overall light-colored. But in the parlance of the natural stone industry, the definition of granite is expanded to include all igneous rocks, as well as many metamorphic rocks like gneiss and schist.
ABOUT ONYX AND TRAVERTINE:
Onyx and travertine are variations of the same stone. They come about from mineral-laden water, like you’d find at the mouth of a hot spring. Both are made of calcite, the same mineral that’s in limestone and marble. Travertine has a lacy pattern from the way the water flows in little rivulets away from the mouth of a hot spring. Onyx can form from either hot or cool water, and is less porous than travertine. Onyx is beloved for its smooth layers and gem-like colors that are especially glorious when backlit.
STAY TUNED TO THE BHANDARI MARBLE GROUP PAGE TO GET TO KNOW MORE ABOUT SUCH FACTS AND HISTORY OF MARBLE AND OTHER NATURAL STONES!