Epidote and olivine are two green-colored stones that some enthusiasts may get confused by.
However, they are quite different and there are some significant variations that you should be aware of so that you can tell them apart more easily.
Epidote vs Olivine (EXPLAINED)
What is Epidote?
The name epidote is used to refer to two things; a mineral group and the most common mineral in the mineral group.
As a mineral group, epidote refers to stones that have a crystal structure of isolated and paired silica tetrahedrons and a shared general chemical composition.
That said, we’re going to focus on epidote as a singular mineral to help simplify the understanding.
As a mineral, epidote is a silicate that is commonly found in low and moderate-grade metamorphosed rocks.
Epidote occurs as it replaces mineral grains that have been altered through metamorphism.
Epidote can appear yellow-green to light green in color and in rarer quantities brownish-green to black.
Physical Properties of Epidote
Epidote has a colorless streak and a vitreous or resinous luster.
On the Mohs hardness scale, it ranks between 6.0 to 7.0. It can be transparent, translucent, or nearly opaque depending on the specimen.
Epidote is a rock-forming mineral and many metamorphosed rocks contain a small amount of this mineral.
Two stones which contain large amounts of epidote are epidosite and unakite.
These two stones are found in relatively rare locations.
However, in the areas where they are found the amounts can be significant.
Epidosite is a metamorphic rock that is comprised mostly of epidote with a small amount of quartz.
It can be found in basalts or ophiolites, which are created by hydrothermal processes.
Similarly, unakite is formed when granite is metamorphosed.
It is created when materials that are less resilient to these processes are altered or replaced by epidote.
Unakite is an interesting pink and green stone that was first found in the Unakas mountains in North Carolina, and it is from this location that it derived its name.
Uses of Epidote
Epidote hasn’t been used in many industrial processes and it has only seen minor use as a gemstone.
However, high-quality stones are sometimes cut and used in jewelry.
While they haven’t attracted as much attention as olivine and its gemstone variety peridot, it can still be quite beautiful in a collection and is commonly purchased by mineral and gem collectors.
What is Olivine?
Olivine is the name given to a group of rock-forming minerals that are typically found in igneous rocks such as basalt, gabbro, and peridotite.
Olivine is usually green in color with hues ranging from a deep olive green to yellow-green and even brown if high levels of iron are present.
Most of the olivine that is found is found on the surface level of the Earth in dark-colored igneous rocks.
These rocks are most commonly found at divergent plate boundaries and in hot spots along the center of tectonic plates.
They are most commonly found in these areas due to olivine having a relatively high-temperature crystallization point.
It is one of the first minerals to crystalize as magma cools and it usually ends up falling to the bottom of the magma chamber due to its higher density.
This can lead to high accumulations of olivine in the lower parts of magma chambers, which can lead to the formation of olivine-rich stones such as dunite.
Olivine is not commonly found in sedimentary rocks, due to the fact that it is prone to weathering quickly.
However, it can be found in sediment and sand if the location is close to the source of the olivine.
Physical Properties of Olivine
Olivine has a colorless streak and a vitreous luster.
On the Mohs hardness scale, it ranks between 6.5 to 7.0. Specimens of olivine can be either transparent or translucent, depending on their composition.
Deep olive green colors of its gem variety peridot are highly favored, although bright lime greens are also popular.
Darker brown hues can also be found in specimens that have high iron content.
Uses of Olivine
Although the gem variety is most commonly known as a stone for jewelry, olivine hasn’t been used often in industry.
Its greatest use comes from being used in blast furnaces to help remove impurities from steel during the creation of slag.
It has also previously been used as a refractory material used to make refractory bricks and casting sand.
However, cheaper and more prevalent alternatives have all but replaced them in this respect.
Epidote and Olivine
When it comes to telling these two stones apart, there are significant differences that you can refer to.
For instance, olivine has poor cleavage and is brittle with a conchoidal fracture.
Epidote has imperfect to perfect cleavage in one direction.
Olivine also has an orthorhombic crystal structure while epidote has a monoclinic crystal structure.
These differences can help tell these two stones apart, and make it easier for you to identify specimens for your collection.
Olivine, and by extension peridot, has been used for centuries and, as such, it has developed some metaphysical connotations.
Commonly, it is associated with bringing good health, balancing emotions and the mind, and promoting a restful night’s sleep.
It has also been called a stone of compassion.
In some instances, this stone was even thought to be able to ward off the evil eye and stave away jealousy, resentment, and bad visions.
Epidote wasn’t officially identified as a separate mineral until the early 19th century and had previously been considered the same as actinolite.
However, today it has garnered an association with increasing energy levels and stimulating the immune system.
It is thought that this stone can aid in healing physical ailments as well as improving mental distress.
While none of these correlations are backed up by science, it is important to understand the properties that a fair many people attribute to these specific stones.
Two Great Stones for Any Collection
Epodite and olivine are two fantastic and interesting stones and their green hues make them quite eye-catching.
By learning their differences, you can begin to more easily tell them apart so that you can be sure of exactly which you have in your collection.