The beauty of natural stone is that no two pieces are exactly alike. Your piece of stone is a unique piece of art forged by mother nature over centuries using heat, pressure, and lots of different minerals and organic materials. The way these minerals settle into the stone is what causes the huge array of colors, patterns, texture, and veining in a given slab. But, what exactly makes some marbles red and some quartzite blue? Let’s take a look!
Marble is made up of crystallized limestone. The less “impurities”, or other non-limestone material the stone has, the more white it will be and the less veining and color variation it will have. In most cases, when marble is forming other minerals can penetrate the limestone mass, giving it different colors and textures. Iron oxide can cause yellow and brown deposits, while iron and feldspar will create pink and red coloration. Looking for something more exotic? Serpentine creates a green hue while porphyry deposits will create a violet coloring. There are also gold, pink, and blue marbles on the market, all of which get their shades from different mineral deposits.
Granite is chock full of color variations, giving the stone its signature speckled, mottled texture. Granite is mainly comprised of quartz, feldspar, and mica, but also often contains other minerals in lesser amounts. Feldspar and hematite are responsible for any white, pink and red spots while hornblende can cause darker green and black variations. Quartz often creates shades of gray, while muscovite, biotite, lepidolite will create specks of silver, black, and violet, respectively.
Limestone tends to have less intense color variations than granite, marble, and quartzite. This is because limestone is made up of degraded stones, coral, fossils, shells, and other organic matter. Spots of iron can cause orange, red and brown streaks while lighter shades of white and gray come from shells of marine animals. The best thing about this stone? It can often have pieces of shells or fossils embedded into it, which could make for a great conversation piece if used as a bar or kitchen countertop in your home!
Like granite, quartzite can be comprised of many different minerals that can give it a huge variety of colors. The most common quartzite will typically be white or gray, and flat flakes of mica can give quartzite a slight translucency. Blue quartzite comes from the mineral dumortierite, whereas iron oxide can cause pink and red spots. Quartzite can also come in purple, yellow, orange, brown, and green — all thanks to different minerals that were around when the stone was forming!
Slate usually comes in dark gray due to the fact that it is largely comprised of clay and volcanic ash. However, iron can turn slate several different colors, including red, green, black and brown. Hematite can also cause reddish or even purple tint while chlorite is responsible for a greenish slate. Slate can also contain pieces of mica, chlorite and quartz, which can change up the texture and sheen a bit, giving it more visual interest.
Knowing a bit more about how different stones are created and where their distinctive colors come from can help you narrow down your options when you’re considering incorporating natural stone into your home. The amount of color and textural variations in each unique slab are truly astounding, so make sure you take the time to go through all of your options. There’s a stone out there with your name on it — you just have to go out and find it!