# Would any structure last longer than the Hoover Dam? **URL:** \ **Category:** Factual Questions\ **Created:** [July 8, 2013, 5:40am UTC](https://boards.straightdope.com/t/would-any-structure-last-longer-than-the-hoover-dam/662917 "2013-07-08T05:40:11Z")\ **Posts on this page:** 1\ **Page:** 3
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [July 9, 2013, 12:54pm UTC](https://boards.straightdope.com/t/would-any-structure-last-longer-than-the-hoover-dam/662917/41 "2013-07-09T12:54:57Z")
> [@the\_diego](#): > > Here’s what you said last: > > Hardness has nothing to do with it. It has lots to do with it > [@](#): > > I’m taking about resilience to weathering and erosion. Which laterite has to a degree, but nowhere near as much as hard rocks, because laterite is only as hard as its cement, most of which is clays. It’s not even the hardest relict pavement - silcrete is. > [@](#): > > My mistake was using the the term laterite when i should have used metal oxides. Same difference - laterite is metal oxides and quartz cemented with clays, but _not_ diagenicized. > [@](#): > > Oxides erode the slowest on the earth’s surface because they are already products of erosion. Naaah. Oxides can alter plenty after initial formation (not erosion, which they can also do, since there’s plenty of physical erosion paths, but weathering) You just have to look at the breakdown of BIFs to see that. Rocks _made_ of iron oxides, but they break down, because iron oxides _looove_ to form iron hydroxides. [quotes] Just not sure how much of Ankor is laterite bricks and how much is sandstone. Maybe you can tell us. [/quote] Maybe you can read the link? " **Most of the visible areas are of sandstone blocks** , while laterite was used for the outer wall and for hidden structural parts. " All those buildings you see? Sandstone. > [@](#): > > Diorite, like granite, has large crystals, some of which erode faster than the others, which is why you eventually have pitting in a lot of quarry facings. I wouldn’t use it. It was [good enough](http://en.wikipedia.org/wiki/Diorite#Historic_use) for lots of ancient artefacts that are still around today. Quarries are not the same as polished surfaces, which is generally what you do to the kind of worked stone you expect to have stick around. > [@](#): > > Meta-sediments (not marble) are my pick. That’s why I said orthoquartzite. But laterite isn’t a meta-sediment of any sort. It’s not even a rock. [Previous page](https://boards.straightdope.com/t/would-any-structure-last-longer-than-the-hoover-dam/662917.md?page=2)