This is a very fine and extremely rare pipe from Venezuela known as a pipas angulares de barro procedentes. There is only one book written on Aztec pipes. "Pipas Precortesianas" was written by Muriel N. Porter. Porter states that Aztec pipes are extremely scarce and "we can almost say that pipes were unknown." There is a drawing in this book of this class/type of pipe. Of course, tobacco wasn't available until the Spaniards introduced it. Most of the pipes that have been found are typical shapes shown in the Sotheby's auction. VERY few effigy pipes were found. I have what I humbly believe is the finest Aztec pipe collection in existence. Three Aztec pipes were sold at Sotheby's auction on March 23, 2013 for $12,890. None were effigy pipes. A picture is attached. E-mail me for a link to the auction as Trocadero does not allow links.
BEWARE, because of their rarity and desirability, these pipes are being churned out in workshops in South America and offered on eBay that are modern made and aged. Ceramic is easy to reproduce, age and patinate. You can not buy a genuine pipe for $100! They very rarely come on the open market.
I purchased this pipe from Gilbert Cooper who purchased it from Allan Brown, a well known dealer in artifacts from Chicago. It was collected prior to 1960. It is a one of a kind, sleepy-eyed human head effigy pottery pipe that is enormous and very impressive. It has a very small chip on the bottom right eyelid which I like because it shows the patina contrast. This is a no-brainer. It measures 8" long by 4-1/2" tall by 2-3/4" wide. The piece is solid.
I would be willing to offer a good deal if one were to purchase all my 5 pipes as a collection. Please view my site by typing in "pipe" to see my other examples. If you would like additional pictures, please e-mail me.