El Salvador contains some of the most amazing stones in Central America.
In this article, you’ll learn more about the geology of El Salvador.
Types of Rocks In El Salvador: A Guide to the 7 Most Common You’ll Spot
The information provided in this article by YesDirt.com is for informational purposes and is subject to change. Laws are updated. Accessibility guidelines and restrictions change. Be sure to confirm the land status and collection rules before you travel to an unfamiliar location or collect any material.
El Salvador is a country with over 20 volcanoes that have resulted in the formation of beautiful volcanic rocks like Basalt, Andesite and tuff.
Although El Salvador does not have any Caribbean coastline it still contains thick limestone deposits and sandstone.
El Salvador does not seem to have been studied extensively by geologists, but the geology of the area is similar to the bordering Guatemala and Honduras.
El Salvador has two very active volcanoes, volcanic craters and lakes that have formed in volcanic craters.
El Salvador has many rivers which are great places to find rock samples in the area.
Sandstone formed from sand grains that cemented together to form a solid stone.
The sandstone found on El Salvador is very old and it is found layered with andesite from volcanic activity.
It is possible to see the individual sand grains in the sandstone. It is usually composed of mostly quartz. Sandstone can be many colors but it is most commonly pale yellow, tan, brown or gray.
The grains of sand that make up sandstone are very hardy to erosion and they may break off of the sandstone and be incorporated into future sandstone formations or other rocks.
Limestone is generally formed in warm sea water when coral reefs, shells and other calcium-containing animals die and their remains become cemented together into a solid stone.
Although El Salvador does not border the Caribbean the areas were formed around the same time.
On El Salvador there is a 400 foot thick deposit of limestone. This indicates that this was once on the ocean floor before it was pushed up by volcanic or tectonic action.
Limestone can vary in color, but it is generally white, light tan, yellow, or gray. Limestone can be identified by an acid test where a diluted solution of hydrochloric acid is dropped onto the stone.
The calcium in the stone produces a vigorous fizz.
Limestone can often also be identified by its relative softness. Limestone has a hardness of 2 to 4 and can be scratched with a knife.
Basalt is a common volcanic rock that is generally pretty dark in color and is formed when low viscosity lava cools.
The lava that forms basalt is about the thickness of peanut butter.
Basalt often contains other minerals like olivine and augite. These minerals often form when the lava is still below the surface and when the compounds cool the minerals may crystalize.
Basalt is a very fine grained rock and it often contains holes or vesicles that are created when the lava is rapidly depressurized during extrusion.
The way the basalt cools can drastically alter the way the rock looks.
One of the most stunning basalt formations can be found in El Salvador at Los Tercios Waterfall.
Los Tercios Waterfall
Rock lovers should be sure to schedule a visit to Los Tercios Waterfall. The rocks here form hexagonal columns and from May to December water flows over this incredible rock formation to create a waterfall.
The rocks are thought to be an unusual formation of basalt that cooled into these striking shapes.
Local legend says that the waterfall is the result of a family’s fabric store being turned to stone after a forbidden love affair between a wealthy woman and an indigenous man.
When you see the formation and the individual distinct hexagonal columns you can imagine bolts of fabric being frozen in time.
Fingerite is a rock that has only been found in El Salvador and it can be found around fumaroles.
The mineral can be found in triclinic shaped crystals. The crystals dissolve in water and should be collected very carefully.
Fingerite has been found in the area of the Izalco Volcano, which has been erupting almost consistently until 1958.
The volcano has been nicknamed “The Lighthouse of the Pacific” because of the constant interruptions.
The basalt formed around this volcano often contains olivine.
Blossite & Zeisite
Closely related, blossite and zesite are both copper vanadate minerals that are often found together.
Blossite is a mineral that was discovered by a professor at Virginia Tech and has been identified only in El Salvador.
It forms very small black crystals with a red brown streak due to the copper present in the mineral. The crystals form around fumaroles in the Izalco Volcano region.
There is no observable cleavage pattern as the crystals are often too small to observe a cleavage pattern.
Zeisite is black, red or reddish brown and forms anhedral crystals. It has thin edges and is transparent with a metallic luster.
Both of these crystals form in the presence of basaltic volcanic cones.
Another vanadium that was first discovered around Izalco in El Salvador, lyonsite is a dark colored opaque metallic rock.
It is black due to its iron content and it forms an orthorhombic crystal structure.
It has since been discovered in Germany and Russia.
Rocks in El Salvador
El Salvador is home to many volcanoes and one of the most active volcanoes in the region. This and the many rivers and streams make it a good place to collect volcanic rock examples.
The fumaroles surrounding Izalco are home of some rare copper vanadium minerals that are only found in this area of El Salvador.
There have been several discoveries of new minerals in fumaroles around Izalco in recent years. Be sure to go look around and maybe you can get a rock named after you!
There are 5 National Parks in El Salvador where the collection or removal of natural material are prohibited, so be sure to obey any posted signage and local laws regarding mineral collecting.
El Salvador has banned all mining of metals in the country after the ecological impact these activities have had on the country.
Years of deforestation and mining have stripped the country of much of its natural resources.
The conservation efforts in El Salvador center around stopping deforestation and supporting the standing forests that remain in the country.
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