Welcome to Unearthed's Q & A section! Each week we will post answers to your geology/rock related questions. Questions can be submitted via our Instagram stories or at firstname.lastname@example.org
Gemstones are minerals that are of such high quality that they are cut, polished or faceted for jewelry making or adornment. A gemstone may have started as a crystal (defined shape/point) or it may have started as a large piece of rough that was then cut and polished.
Most gemstones in their original pre-polished and uncut form could be referred to as crystals. It is more accurate to refer to them as minerals. While most gemstones started off as crystals, not all crystals are gemstones.
For example, many people are familiar with the gemstone Emerald. However, the true mineral name of emerald is Beryl. Beryl in the common form, even as a crystal may not always be "gemmy" or gemstone worthy. It may not exhibit the clarity or color desired for jewelry making. High quality beryl that does exhibit better clarity or color can be classified as a gemstone. When beryl is high quality, gemmy, and green it is called Emerald. When beryl is high quality, gemmy and blue, it is called Aquamarine.
When most people think of a crystal, they think of a point like on a classic quartz crystal. However, crystals can form in many different shapes such as points, cubes, rounds, clusters, etc. Sometimes minerals do not form into defined crystals and form as a mass or free-form.
Even the same mineral may form in a variety of shapes and colors depending on the growing conditions of where it was formed. It is ok to use the terms mineral and crystal interchangeably when referring to a collection since most minerals you would be collecting are already in a crystal shape.
A crystal's color is determined by several factors including its chemistry, and exposure to radiation or heat. The first is the chemistry of the original mineral. Quartz for example, has a starting chemistry of SiO2 (silicon dioxide). This is the basal chemistry of quartz in it's purist form and results in a clear or white crystal. However, the chemical addition and substitution of small concentrations of other elements such as iron, aluminum, manganese, etc. can alter the color of the mineral.
Amethyst for example, is a purple variety of Quartz. It is thought that small concentrations of iron within the original solution underwent natural irradiation and heating within the earth which caused the mineral to turn from clear to purple.
For mineral specimens or crystals in your home collection, cleaning is best done with an air duster or air canister which is available at most stores. The same as you would clean a computer keyboard, hold the air canister approximately 6”+ away from your crystals and in a light sweeping motion, blow air over them.
Some crystals are hardier than others. For example, quartz/amethyst and agate can typically be cleaned by running under cool water, or wiping with a soft cloth. However, other crystals require a gentler approach. For example: celestite would be best cleaned with an air canister. If you are unsure, feel free to reach out to us at email@example.com! We would be happy to answer your questions in regards to cleaning and handling your items.
If you are a rockhound and your crystals are covered in dirt straight out of the ground, it is best to clean as much of the host material/soil off prior to chemical cleaning. Warning: If your minerals are water soluble for example halite or gypsum/selenite, do NOT wash them in water (this could dissolve the crystals). Most minerals/rocks are not water soluble. For those that are non-water soluble, you can rinse in water or place in a bucket full of water. I like to use a soft bristle toothbrush and water on our smoky quartz crystal finds. If there are stubborn stains or dirt in small cracks or grooves, you may want to try chemical cleaning.
For energetic cleaning of your crystals, many people like to place their crystals in the light of the full moon. If you are doing this, make sure your crystals won't undergo a huge temperature flux at night which could cause them to crack or fracture. Others use sage smoke to clean their crystals. Placing your crystals on or around selenite or gypsum can also clean their energy. Running under water is also an option for non-water soluble crystals (see above).
What's wild is true orange and red minerals are more uncommon than other colors. For true red, I like iron-included quartz, cuprite and petrified wood. For orange, obviously copper! I also really like crocoite, it is an obscure mineral largely found in Tasmania, Australia.
My favorite rocks and minerals for are Smoky Quartz and Petrified Wood. Black Tourmaline is also an excellent grounding stone. Really anything you find that activates the Root Chakra is good for grounding energy. While books on the metaphysical properties of stones are a great place to start, really you should follow your intuition and go for what you are most drawn to. For me personally, I find keeping Petrified Wood in the living room in particular to be very powerful. It's the center-point of most homes where we tend to spend the bulk of our time. There's a physical and energetic 'weight' to that stone that allows for excellent grounding. I think the rooting energy from the original tree, the lithified nature of the tree being crystallized into stone really produces a nice home-base energy.
Moonstone is a gemstone in the feldspar family. There is much debate as to the specific characteristics defining a Moonstone. Typically it is referred to when a potassium feldspar displays pearlescence or chatoyancy. This causes the stone to "flash" different colors when light is reflected at a certain angle. Classic Moonstone typically appears a light color such as white or cream and then flashes colors when tilted in the light (such as rainbow moonstone). I could not find any information indicating a geologic difference between Black Moonstone and the classic white colored Moonstone. My guess is it is very similar chemically to classic moonstone but with a darker matrix.
Whenever possible, we try to get our inventory directly from the miners or fossil hunters themselves (including us)! Typically we see these folks several times a year at gem shows or trade shows. Buying direct from the source miners helps reduce costs for everyone and supports local and smaller mining operations.
I love Larimar! It is a stone currently only found in the Dominican Republic. It is a sea-blue stone with white and blue wave-like patterns. In my opinion the Larimar with the most vibrant depth of color and color contrast with fun white patterning is the best.
Geologically, it is a blue variety of Pectolite (not as sexy I know), a silicate mineral that is found in igneous rocks. This deposit in the Dominican is the only known locality of this beautiful blue stone. It is thought that a small concentration of copper substitutes for the calcium in classic pectolite which causes the blue coloration. And we all know how I feel about anything with copper in it....(I love it).
Metaphysically it is a stone to help with communication, getting in touch with the Goddess energy and like the beautiful cool blue seas it is found near, it promotes a calming cooling energy.
Pseudomorphs are a very cool occurrence. The name means "not genuine" (pseudo) and "form" (morph). Pseudomorphs occur when a mineral has the outward form or appearance of another type of mineral, but the internal chemistry is different. The original shape of the starting mineral remains, but the color, hardness, luster, etc. change to the replacing mineral. Think of a shape-shifter from your favorite sci-fi or comic book story. They may look like one thing on the outside, but inside they are completely different!
Pseudomorphs can form in a variety of ways:
Removal - the original mineral is removed by solution or other means which results in a cavity or mold. The second crystallization occurs within this cavity or mold (similar to how jello can be shaped into whatever mold you put it in).
Substitution - the original mineral is removed while a simultaneous replacement by another mineral takes place without any chemical reaction between the two.
Alteration - the original mineral undergoes chemical alteration with either a loss or gain of a constituent, or a partial exchange of constituents. This results in a mineral with similar chemistry, but slightly different: i.e. malachite after azurite, or limonite after pyrite.
Typically, when you find a pseudomorph in one area, you are likely to find more within the same area. This is a result of a similar geologic occurrence affecting like things in the area.
As a fun side note: Petrified wood is also formed by replacement where the structure of the tree or branch remains but the organic material is replaced by crystalline silica. While it is a similar process, Petrified Wood is not considered a "true" pseudomorph because the original material (tree/organic) was not a mineral.
While the bright blue-green to teal color may look similar, the underlying formation of Gem Silica and Druzy Chrysocolla is different. Druzy chrysocolla is actually chrysocolla with a thin layer of clear or white druzy quartz that has grown on top of the chrysocolla. There will be two visible layers if you look at a cross section of druzy chrysocolla. The first is the blue-green chrysocolla formation. The second is the top layer of tightly compacted, sparkly quartz points (druzy). Gem silica, while a similar color, when cut in cross section is one layer.
Both varieties get the blue-green color from the presence of copper. Gem silica is a variety of chalcedony, chrysocolla is not. Gem silica will not have individual crystal points visible, it will appear as a more massive formation that is then cut and polished.
We'll save this for another much longer post :)