Sandstone or Limestone, the Dummy Differentiation - The Freelance Files MMCXXXI

layered, gray (not white) limestone

We tend to be careful about calling on the Antisocial Network staff geologist (yes, we have one) for the frequent occasions in which we find clueless freelancers pretending to help earth science students with their homework, especially when it's obvious that the freelancer in question knows next to (or precisely) nothing about the topic. Nevertheless, from time to time we awaken the guy from his nap and shove a printout of the post under his door. We've transcribed his comments below for the Hunker.com post, "How to Identify Sandstone Vs. [sic] Limestone" as barfed up by one Jonathan Shaffer.

Shaffer's bio allows that he wrote concert reviews for a while before "working on a Bachelor of Business" at the time he visited this particular chapter of dumbassery on the internet. Without further ado, let's have a look at some of the stupidification he caused, beginning with the claim that,

"All rocks have unique properties that set them apart... Limestone is used in the construction industry because of its abundance and hard physical nature. Sandstone is created from particles of other rocks and sand. It is not as dense as limestone..."

It's a shame that differentiation between the two is not a simple as comparing how "dense" two rocks are, especially given that Johnny probably doesn't know what density is. Since eHow (where he wrote this in the first place) required 300 to 500 words in its posts, Shaffer had to pass along more "information." 

Sadly, much of what he had to say was, at best, ambiguous; at worst, just plain wrong. We're talking about claims such as (corrections provided by geology-guy),

"Sandstone is created in layers. If you can see horizontal lines through the stone indicating these layers, you can be sure that it is sandstone and not limestone." – Sorry, John, sandstone can be massive (no visible layers) and limestone can be finely laminated (see image above).  "Because sandstone is made up of many types of rock and sand, its coloring can be blue, red, brown or even green. Limestone however is always white due to its calcium makeup." – According to the geo-guy, "Bullshit!" A) Sandstone is not made of "types of rock," B) limestone is largely composed of calcium carbonate, not calcium, and C) limestone is RARELY white. "Since sandstone is made up of many small sand particles, it will break apart fairly easily while limestone is much harder and should not crumble." – Hardness of a hand sample is not diagnostic; many sandstone specimens are quite well-cemented and therefore will not crumble.

Where Shaffer completely missed out is the mineralogy of the two rock types. Limestone is predominantly calcite, whether fossils/fragments or lime mud; sandstone has both a specific texture of sand-sized grains cemented together by a mineral precipitate.

Then again, geo-guy admits to knowing next to nothing about marketing and double-entry bookkeeping. Unlike our Dumbass of the Day, though, he doesn't post internet content pretending to be an expert on such topics.

SI - SEDIMENTOLOGY