Black Die?

[johno]

Hi, i have just uprooted a plant when changin round my tank and when i lifted it out of the sand a load of black coloured kind of die came out

the plant kid of looks like a mini palm tree, ill try get some pics when i can

for now ive took them out!! any idea what this is? and will it be harmfull in the water?

 

[Ludwig Venter]

Do you have a very fine gravel or is it coarse??

 

[johno]

Do you have a very fine gravel or is it coarse??

Sorry forgot to say, ive got sand.