Citrine has many forms, but not all of the stones called by this name are truly Citrine. Amethyst in disguise is only the tip of the iceberg!
First of all, let's start with what Citrine IS. Citrine is a variety of Quartz, Silicon Dioxide, that has yellow, yellowish green, or yellowish brown coloring. Citrine is found in locations all over the world but is considered rare in its natural form, as seen here.
The most common way that false Citrine is created, is to heat Amethyst at high temperatures until it turns orange. All bright and dark orange Citrine is in fact heated Amethyst. Below is an Amethyst geode that has been cut in half, with the right side heated to produce orange Citrine. The orange can range from bright to dark, brownish orange but always orange. True Citrine is never this color, although sometimes Amethyst is heated to orange naturally.
Genuine Citrine will always have yellow based coloring. It can be pale yellow, yellowish brown, yellowish green, bright yellow, or even yellowish orange like this Citrine:
It can sometimes be so similar to light Smoky Quartz that it is impossible to discern between the two, in which case either name is correct. This rare Smoky Citrine here is from the Congo and often called Kundalini Quartz. This coloring can also be referred to as "honey" Citrine.
This one has dark, smoky phantoms in yellow Citrine, cut and polished into a point:
These are also natural Citrines that have been cut and polished into points. These ones are from Brazil:
There are other instances where crystals are mistakenly called Citrine due to their color, even though they are completely natural.
One example is when clear Quartz is coated in iron oxides that are yellow or orange in color. These naturally occurring coatings can be opaque or translucent, but some people mistake the overall orange or yellow coloring for being Citrine.
Spirit Quartz is another crystal that I see being called Citrine quite a bit. These crystals feature a Quartz or Amethyst crystal that has a second generation of smaller Quartz or Amethyst crystals formed along the sides.
They occur as Amethyst, or white Quartz, but never actual Citrine, or Ametrine, though both often have some orange or gold colored iron oxidation.
True Ametrine, the bicolor mix of Amethyst and Citrine, is very rare and only legitimately mined in Bolivia at the Anani Mine site. It is also called Bolivianite. Sometimes Amethyst has orange iron oxides in it and will appear similar to Ametrine, but you need to be very careful about location and identification.
This is a genuine, bicolored Ametrine from Bolivia that has been faceted for jewelry.
So keep in mind that there is much more to Citrine than just the color of the stone! And maybe keep a real one in your pocket or on your desk if you're looking to make better money ;)
Crystals are pretty pieces of nature that we keep around because they're beautiful or make us feel happy. But crystals are also used in a lot of other important ways that most of us don't even think about.
Sugar is a very common type of crystal that we all know- Americans consume an average of 20 teaspoons a day!
Another crystal we love to eat? Salt-or sodium chloride- occurs naturally when saltwater evaporates, leaving cubic salt crystals.
Quartz is used in watches and clocks to keep accurate time, by sending electricity through a Quartz crystal. The electricity makes it vibrate at a precise frequency which regulates the movement of the clock or watch!
Graphite is a crystalline form of carbon that is very soft and has many uses. It is mixed with clay to create the 'lead' of pencils, which actually have no lead at all. Graphite is also used as a lubricant, conductor and plays an important role in Lithium batteries.
Silicon is an important ingredient to making computer chips and processors, so you can thank crystals for your smartphone and your laptop. LCD screens are Liquid Crystal Display. The liquid crystals are great at carrying light precisely so they make great screens.
Drywall is often made of gypsum, so you are likely surrounded by it right now if you're inside.
And if not, maybe you're surrounded by another type of crystal- snow- which is crystallized water.
These are just a few examples of crystals that we use or see in everyday life- besides the ones we keep for their beauty or metaphysical properties. Crystals are everywhere!
Sometimes a Quartz crystal will have a little pocket inside it, with liquid that moves around. You rock it side to side to watch the bubble move up and down and it is usually mesmerizing. These are often called enhydros. I call them that. Funny thing is- that’s NOT an enhydro! These are actually called fluid inclusions! An enhydro is something else altogether and I’ll get to that soon - I promise!
First, how do these liquid inclusions occur? When the Quartz crystal is forming, often from hot groundwater containing silica, there can be inconsistencies in the layers, where some parts form more quickly than others. In some cases this could cause a small pit to form. This pit, while full of water, is then sealed off when the Quartz continues to form over the pit. This leaves a pocket that is completely full of water.
Next, as the crystal cools, so too does the liquid inside- and both contract (become smaller in volume). The water contracts more than the crystal does, so that the liquid inside the pocket becomes smaller than the pocket itself. The liquid pulls away from the walls of its pocket, forming a little vapor bubble that can move around the pocket.
Vapor bubble formed inside Quartz
Milky Quartz gets it’s white color from tons of microscopic fluid inclusions. How crazy is that?! And the liquid trapped inside a crystal isn’t always just water. When hot saltwater gets trapped inside of Quartz, the salt can crystallize into a tiny Halite crystal! Herkimer diamonds from New York often have fluid inclusions with Carbon in them, which look like black specks. Some Quartz from Pakistan have Petroleum inside them, as well as Fluorites from Elmwood, Tennessee. Liquid inclusions vary so much- and they are tiny time capsules to geologists- a pure sample of the liquids present when the crystal formed!
So what is an enhydro?
An enhydro is defined as “a hollow nodule or geode of chalcedony containing water, sometimes in large amounts.”
Therefore, liquid inside Quartz it is not a true enhydro. Chalcedony is a micro-crystalline variety of Quartz (made up of many microscopic, elongated Quartz crystals), but Quartz is not a Chalcedony. Some varieties of Chalcedony include all Agates, Onyx, and Jaspers. So since Agate is a Chalcedony, that means that Agate geodes that have water trapped in the hollow center ARE in fact, true enhydros. They are probably the only liquid inclusion I know of that do fit the true definition of an enhydro!
Another difference between the two, is that with a liquid inclusion, we talked about how the liquid is forever trapped, and unless opened up that liquid will stay the same as it was the day it was trapped, for all eternity. But in an enhydro, the stone is porous, and the water actually is able to seep in and out of the geode! So the water inside could be from the time just before it was collected, rather than the time the stone itself formed. Once collected, the water can continue to seep out, though very slowly. Some seal them to keep this from happening.
Agate Enhydro Geodes
Now, I know that most folks already call liquid inclusions enhydros regardless of what type of rock they’re in, and that most people don’t know the difference. I’ll have to keep calling them enhydros so that people know what I’m talking about and can find them in my shop. But it’s still a fun bit of knowledge for you to have up there in your noggin!
There are so many different crystals and gemstones that exist in nature, and collectively they have an incredibly vast range of colors all over the spectrum. Some types of gemstones can have several different colors, like Topaz, Quartz or Tourmaline. So how do they get their colors?
In their chemical structure, gemstones have trace amounts of different transition metals either as part of their chemical compound or as impurities. Transition metals are the metals that make up the large, middle part of the Periodic Table, and these metals are able to absorb colored light. Different wavelengths of visible light can be absorbed by different transition metals, leading to the different colors that we see.
Purple Amethyst - colored by the irradiation of Iron ions in place of Silicon
For example, the purple coloring of Quartz that we call Amethyst is caused by the irradiation of Iron ions in place of Silicon in some locations of the structure.
Garnet’s red coloring is caused by Iron ions replacing Magnesium ions, and the lovely blue variety of Beryl that we call Aquamarine is from the presence of Iron ions replacing Aluminum ones.
The yellow color of Citrine - another form of Quartz- is caused by Aluminum or Iron impurities.
In Emerald, Chromium ions replacing Aluminum creates green. In Ruby it creates red!
Topaz in it’s pure form is colorless, while atomic level imperfections cause the blue, yellow and brown varieties.
Topaz in it’s pure form is colorless, while atomic level imperfections cause the blue, yellow and brown varieties.
Transition metals are not the only way that gemstones get their colors, however. In some stones, such as Sapphires, it is caused by the transfer of electrons between ions.
Color can also be caused when an ion in a specific place is missing within the structure, or diffraction of light through the structure, like in an Opal.
Simple inclusions of tiny minerals inside a larger solid crystal can change its color. For example if a clear crystal like Quartz or Apophyllite or Calcite has red Hematite in it, the color of the crystal itself can appear to be red.
These are the most common reasons for the colors of crystals, or at least their colors as they appear to the human eye. There are more reasons, for more complicated crystals such as Alexandrite, Labradorite and some Fluorites. Crystals are complicated and the more you learn, the more complex they become!