Rock coloring theories

Dear blog, 

There is a unique coloring on the rocks that make up the cliffs by some of the coves in laguna beach. This image perfectly encapsulates all of the colors. Pink, orange, white and a greenish blue that appears all over the cliffs of Fisherman's cove. 

All over these cliffs you can see the vibrancy and uniqueness and patterns of the coloring that stain what I believe to be Topanga sandstone. This cliff is located in laguna beach in a little cove called Fisherman's. This cliff often erodes, sometimes dropping onto you if you sit close enough, covering whatever you have below it in little bits of rock.

 Every time I come to Fisherman’s cove I spend my time wondering why this specific cliff became so wonderfully colorful and so beautiful. I did some research and this is what I came up with. 

It was actually quite hard to come up with a concrete answer as to why there is such unique coloring on this cliff however here are some theories. I believe the bright whites on the sandstone are caused by a thing called Caliche or Calcrete. Caliche forms in arid or semi arid climates when calcium carbonate dissolves in water and cements onto a rock or soil particle, forming a hard layer. 

*Calcium carbonate is made up of calcium, carbon, and oxygen atoms. Calcium carbonate is a main component of marine organisms shells and skeletons such as corals and mollusks. 

Since this cliff is so close to the ocean water, it is likely that the decades of ocean spray caused a buildup of calcium carbonate on the cliff causing it to turn white. 

Example of white coloring and pink and purple coloring lining the white coloring

I am still quite stumped by the pink coloring around the white deposits. I thought it may be the presence of  hematite but quickly discarded that theory because there would be pure pink deposits. Which there are not. 

I think it may be some reaction that the calcium carbonate has with the sandstone causing the areas around it to start to turn pink.

There are however pure white deposits... which makes it quite confusing. 

It can also be observed that near the white and pink coloring, the sandstone becomes a darker yellow or even orange and avoids the green part. I am still unsure what chemical causes it to be this color. If I find out I will update this. 

The green in this rock could be due to the presence of green clay mineral glauconite. Glauconite: greenish clay mineral, rich in iron and potassium, that forms in shallow marine environments and can be found in shallow marine sediments. 

The Glauconite theory  goes as such: Glauconite could have intruded upon the plain sandstone through the sand and ocean spray and mixed with it turning it into greensand (sandstone rich in glauconite). 

It can be observed that the most full coverage green area is closest to the sand which could lead one to believe that the tide was once much higher and caused the large lower bit of the rock to be green through direct contact. 

It can also be observed in these images that the large green coloring does not occur above the pink and white coloring which can lead one to believe that the green was caused from direct contact from the water and sand and the white was caused from the spray.

Here is an excellent example of the divide of the green and pink and white coloring. 

A closer look

There are darker more sporadic bits of green coloring that occur next to the pink and white coloring. I believe that is caused by spray as well instead of direct contact because of how scattered it is.