Chinese Name：沼澤橡木
English Name：Bog Oak
Chemical Composition：It's a kind of semi-fossilizied wood
Crystal System：Amorphous, Organic Material
Hardness：Harder than normal oak
SG：Higher than normal oak
Related Chakra：Root
Locality：Ukraine, Ireland, England, Siberia, Russia
Colour：Dark Brown to Black
Remarks：Bog Oak is a back semi-fossilized wood which is 5,600 years old.

Oak that has been buried in a peat bog for hundreds or sometimes thousands of years. The extremely low oxygen conditions of the bog protect the wood from normal decay, while the underlying peat provides acidic conditions where iron salts and other minerals react with the tannins in the wood, gradually giving it a distinct dark brown to almost black color.

Bog-wood may come from any tree species naturally growing near or in bogs, including Oak (Quercus – "Bog Oak"), pine (Pinus), Yew (Taxus), Swamp Cypress (Taxodium) and Kauri (Agathis).

Tone and coloring power depended on natural conditions and mineralization period. To gain black color the oak needs the fuming period from 1000 up to 2000 years.

Formation of the oak deposit happen owing to some necessary conditions:
1. Oak-woods on the river banks
2. Speed of the river current favourable for the process of mineralization
3. Saturation of water with mineral salts
4. Certain structure of the river fluvial sediments and time factor.

It follows from this that bog oak is really unique material because the probability of coincidence of the above-listed factors is rather low.