Selenite and satin spar are two of the most commonly confused crystals, and most people have a difficult time telling them apart.
While they may come from the same mineral, these two crystals are distinct and there are a few key ways you can identify them.
Selenite vs Satin Spar: Explained
What is Selenite?
Gypsum is an evaporite mineral that is most commonly encountered in layers of sedimentary deposits.
These crystals can grow quite large, with the largest selenite crystal being 12 meters long and weighing 55 tons.
Selenite is a soft mineral, with a hardness of only 2 on the Mohs scale, and it can easily be scratched with your fingernail.
This crystal is most often found to be almost transparent and nearly colorless.
If a color does occur in selenite, it’s usually due to the presence of additional minerals.
When formed, it’s usually in flat thin sheets that can easily be flaked apart.
A great many of these sheets can be found in Utah.
The term selenite has often been used synonymously to refer to any form of gypsum, which has led to a lot of easy confusion.
What is Satin Spar?
Satin spar is another form of gypsum, although it has distinct differences from selenite.
For instance, its coloration is slightly different.
Satin spar often exhibits more coloration than selenite and it is more fibrous and silky.
It’s not as transparent as selenite and can appear quite pearly when polished.
The term satin spar was originally used to describe a form of fibrous calcite, which can be distinguished from gypsum satin spar due to its greater hardness. (A 3 on the Mohs hardness scale.)
Satin spar is also much more common than selenite, despite them being from the same mineral.
Similarly, some retailers will actually sell satin spar under the name selenite because it’s less costly to buy and the two are so often confused.
Gypsum as a Mineral
Gypsum can be found on every continent and of all the sulfate minerals it is the most common.
Because it is an evaporative mineral, it is commonly found in clay beds, evaporated seabeds, caves, and salt flats.
Selenite, for instance, is commonly found in the Great Salt Plains of Oklahoma and the Salt Plains in Utah.
Anhydrite forms when gypsum is dehydrated.
However, if reintroduced to water, gypsum can reform in any of its four varieties.
One instance of this is found at the Philips Copper Mine in Putnam County, New York.
Here, selenite microcrystals are commonly found on numerous surfaces.
Selenite and Satin Spar (How To Tell Them Apart)
When it comes to telling these two crystals apart, there are some key points you should keep in mind.
Selenite is often much more transparent, and satin spar much more milky and opaque.
Fibrous satin spar can also exhibit chatoyancy, or ‘cat’s eye’ effect, that selenite does not.
Similarly, satin spar will almost always be prismatic, while selenite will appear more see-through, almost like sheets of mica.
Because of this sheet-like property, selenite has even been used as window glass in the past.
Language Confusion Of Selenite and Satin Spar
When looking to purchase either selenite or satin spar, it’s worth noting that in some languages the roles are reversed.
For instance, in Russian, selenite refers to the more fibrous variety of gypsum that we would call satin spar.
Likewise, what we would call selenite, in Russian, would simply be called gypsum.
This can lead to translation confusion, leading to a larger need for visual identifiers.
Keep this in mind when purchasing, and always check where your crystal is being shipped from so that translation differences don’t get in the way.
Marketing Confusion Of Selenite and Satin Spar
Similar to how the terms can vary between languages and locations, retailers will often use selenite’s popularity to market satin spar using the wrong name.
This is because selenite is more well-known, and since many people have difficulty telling the difference, most don’t realize the error.
What to Remember When Purchasing Of Selenite or Satin Spar
If you’re looking to purchase selenite, look for specimens that are clearer and more sheet-like in appearance.
A pearlescent finish or milky color almost always signifies satin spar, as opposed to selenite.
Similarly, a satin spar crystal is much more fibrous and when polished will exhibit chatoyancy.
These differences can help you more readily identify these two distinct crystals and ensure that you’re getting the one that you want.
The Uses of Selenite and Satin Spar
Gypsum, as a mineral, has many uses and can be found in plaster, shampoos, creams, and even some tofu.
Selenite has even been used to form window panes, as demonstrated at the Santa Sabina church in Rome.
However, today, many people know selenite and satin spar for their attested metaphysical properties.
The Metaphysical Properties of Selenite
In many different cultures, selenite was reputed to have healing benefits.
Today, this tradition has continued and many people use selenite to help promote calmness, enhance mental clarity, and clear blocked energy.
However, due to popular trends that involve ‘charging’ crystals in water, it should be noted that selenite and water do not mix.
Selenite will dissolve in water, making the water undrinkable and ruining your crystal.
The Metaphysical Properties of Satin Spar
Similar to selenite, satin spar crystals are often associated with cleansing and promoting a calm atmosphere.
Satin spar is also commonly shaped and sold as wands, crystal balls, and palm stones.
This is due largely to their prismatic effects and their chatoyancy.
Satin spar should also be kept away from water, and because it is so soft, it should not be carried around with other stones.
If placed in a bag with harder stones, it can easily be damaged and ruined.
While none of these properties are scientifically proven — aside from the crystals being damaged by water — these are some of their most popular uses in the modern day.
Gypsum in Many Forms
Selenite and satin spar are just two of the four forms that gypsum can take, and they can be difficult to tell apart if you don’t know what to look for.
Keep in mind the visual identifiers of these two crystals so that you’ll be better prepared to tell them apart in the future.