Thread: Yellow flecks in Merbau - what are they?

They are "mineral salts" (Ca or Si compounds or Aluminium succinate) that are deposited in the capillaries of the wood. Various research papers mention them, and there have been some stageringly large finds of those deposits in shakes in trees. Other woods display them as well, most noteable are Northern Silky Oak (Cardwellia sublimis) and Kwilia / Merbau.

An Occurrence of Aluminium Succinate in Cardwellia sublimis F. Muell. | Nature

Deposits in heartshakes in wood - ProQuest

Mineral Deposits in Some Tropical Woody Plants on JSTOR

Inorganic Extraneous Constituents of Wood, Holzforschung - International Journal of the Biology, Chemistry, Physics and Technology of Wood | 10.1515/hfsg.1979.33.2.47 | DeepDyve

Originally Posted by RSD

I'm doing a few things with Merbau at the moment and the timber has tiny yellow "flecks" in it - can anyone tell me what that is? At first I thought that it was paint off a painted blade like a Dewalt but then I sawed it and kept finding the flecks even though I don't use painted blades.

I have always assumed they are not mineral salts (that DO occur in tropical woods) but rather a yellow organic pigment / dye in this species. Do some tests to confirm it with Merbau shavings. The pigment dissolves in water and metho. I believe solutions of the pigment will fluoresce in sunshine or best in UV (black) light.

Also I have heard fresh merbau should not me stored or placed on concrete as it forms a dark stain due to this pigment reacting with concrete.

Euge

Here is a technical paper for those who are interested in the pigment found in Merbau and Afzelia

Topochemical investigation on phenolic deposits in the vessels of afzelia ( Afzelia spp.) and merbau ( Intsia spp.) heartwood, Holzforschung - International Journal of the Biology, Chemistry, Physics and Technology of Wood | 10.1515/HF.2006.099 | DeepDyve

Many thanks for the replies everyone - interesting!

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