Aug 20 2007
The Rock that Floats
The confusion arises as follows:
[…] One finds the amber in the 
One also finds pieces of amber floating on the water of a considerable weight. Sometimes those pieces are really big. […] One can find it among the perfume makers at
— Abu Zaid al Hassan from Siraf & Sulaiman the Merchant, Travels in Asia, 851 AD
Reading this ancient travel-report, anyone marginally familiar with amber will note several odd discrepancies. No one knows where it comes from? Found at the East Coast of
After a brief logical consideration, anyone will conclude that the amber mentioned here is something entirely different than our beloved Amber – that yellow-golden-brown-colored fossil resin.
Indeed it is. What Abu Zaid was speaking of was of course ambergris, which is, bluntly put, ‘sperm whale vomit’. It is an oily perfumed substance secreted by the sperm whale and cast up on the shore, where it would then be found by the… erm.. camels. Our English word ‘amber’ derives from the old Arabic word ‘anbar () and refers quite obviously to this waxy but very valuable substance and not to the fossil resin. Puts the usage of ‘Amber’ as a female first name in shocking contrast, doesn’t it? Since fossilized amber was initially found on the shores much like ambergris, the linguistic confusion was complete. In addition, translated ancient documents, particularly those from Pliny the Elder’s work Naturalis historia may also pertain to the origin of the term amber as applied to the fossil resin (for a more complete etymology of the word ‘amber’, click here).
So besides this dodgy whale upchuck, are there any other types of gray Amber that float?
Now, it’s a well known fact that amber floats in saltwater. But with all the unique forms of amber that are found – Blue Amber, Insect Inclusions, Green Amber, Bony Amber, White Amber, Cognac Amber, etc – here is yet another one: Foamy Amber.
It can be classified alongside White Amber, Bony Amber and Cognac Amber, since their origin seems to be of a similar nature. The turbidity which is the key factor in defining these names given to amber is not the result of any chemical, or the affect of any inclusion trapped in the resin. The turbidity is
a result of thousands of tiny air bubbles held in the amber. The size and density of the air bubbles results in different shading. The size of the air bubbles range between 0.00017 mm - 0.02 mm. The smaller air bubbles packed densely together, about 9,000,000 per square millimetre produces the bastard forms of amber.
Amber Collector Garry Platt — http://www.gplatt.demon.co.uk/properti.htm
Dominican Foamy Amber is probably of a similar origin. Its appearance is a brown-gray, very light mass, reminding more of a fossilized sponge than of amber. It almost floats on normal water due to its high content of air bubbles, yet still can be nicely polished.
How all the air got in there is a matter of speculation. There is little information as to the formation of Foamy Amber, except that it must have developed pre-fossilization involving air, liquid sap and possibly water. This find is very rare in the