Malachite’s beauty really speaks for itself, so I am not going to bother with all that. Instead, let’s talk about the fun stuff; chemistry and geology!
A gorgeous example of a malachite stalactite from crystalclassics.co.uk
To begin this journey, we need to know about primary and secondary minerals since malachite often occurs as a secondary mineral. A primary mineral is one that forms during the original solidification or crystallization of the rock. For example, minerals that formed from lava flows or deep underground under immense heat and pressure. When these original rocks undergo weathering (either physical or chemical) they are broken down and are free to mix with water and other chemicals or minerals in the vicinity. Eventually this new mixture solidifies and a secondary mineral is created. I always picture making cake pops when I think about this:
- Our primary mineral would be the original cake that we bake in the oven/volcano.
- When we crumble the cake up we are physically weathering it, kind of like erosion.
- Then we mix our crumbles with frosting just like the primary mineral gets mixed with water and other minerals.
- Finally, re-forming our mixture into a cake ball is like the rock re-solidifying into the secondary mineral.
- Yum!
To make malachite, we start with a cake of copper. Acidic rainwater dissolves the copper (chemical weathering) into a mineral rich solution, if this solution trickles into limestone (our frosting) a chemical reaction occurs resulting in a beautiful malachite cake ball! Well, almost. There is one more important step that applies to malachite stalactites.
An uncut stalactite formation from geology.com
We’ve covered the ingredients malachite is made with, so now let’s talk about the shape and those beautiful bands (sadly, this is where my cake pop analogy breaks down). Once our mineral rich solution is made, it continues seeping downwards through porous rocks and cracks until it reaches a barrier. Malachite can take a few different forms, but in the case of stalactites (my favorite formation) the solution finds its way into an open cavity in the rocks where it drips from the rooftop, leaving a minuscule amount of minerals behind with every drip. A whole bunch of time passes and drip by drip, a stalactite is formed - just like a gorgeous green icicle!
A polished stalactite from crystalclassics.co.uk that shows the natural formation as well as the interior banding...and makes me giggle ;)
Some of these formations are left whole and function as display pieces, but if we slice that stalactite up, we are treated to a gorgeous display of alternating light and dark concentric rings of vibrant green. These variations are caused by differences in the amount of minerals present in the solution over time, and the amount of groundwater that passed through the primary mineral. Almost like the earth is making little watercolor paintings in stone, sometimes the paint is bright and intense, and sometimes it’s a little more watered down.
(How many analogies can I cram into this blog post?!)
Malachite has gone through quite a journey before it ends up on my bench. I sometimes get a little lost staring at these little natural wonders* and trying to get a grasp on geologic timescales and chemical processes. You gotta love a stone that can be so gorgeous and inspire such wonder and appreciation! If you’d like to see what malachite pieces I have available right now click here, or feel free to reach out and see if I have anything new in the works!
