Looking at it to me looks more root like instead of wood. But as long as it's a dense piece I don't think you have to worry, just do as MrBrongher said for soaking, some people like to boil. I soak for a week or 2 depending on how much tanins come out of the wood. I have a large piece of DW in my 40g, only soaked it for a few days(cause I got no patience) my tank had brown water for quite a while even with weekly water changes but I still have a 7.0 ph in that tank and the fish seemed happy. That would look nice with moss and anubias or java fern on it.