[Cob] cob: sand

[Amanda Peck]

My recollection is that there are basically two types of sand.

Silica sand often (not always) has nice sharp edges, which are what you want 
for most building purposes.  It's also what gets melted down for glass.

Coral--or ancient coral, i.e., limestone--sand.  What you find on tropical 
beaches, for THE MOst part (there's a very active kitten helping me this 
morning!).  And from the search I just did, the Aquarium people hate it.

I gather that rounded sand is particularly dreadful for mortar.  IIRC, the 
cob books recommend against coral or any rounded sand.

Aha! found a link that says what I want it to! (South Carolinians pronounce 
their town Beeuw-fort, in North Carolina it's Bo-fort).

http://www.co.beaufort.sc.us/bftlib/beachsan.htm

For more than you ever wanted to know about why rounded sand is bad for 
building, read Sara Andrews' mystery Fault Line (it's available in what's 
called MASS MARKET paperback, which means NO DISCOUNT when buying it 
on-line), my nearest--not-very-good but a real bookstore--bookstore carries 
it, so yours might too.

http://www.amazon.com/exec/obidos/tg/detail/-/0312253508/104-3371032-2299116?v=glance

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