I have a small lump on my left hand in between my thumb and first finger near my wrist it has a blue/black colour to it. what is it please?

Ganglion?: Most likely a ganglion cyst arising from the wrist joint or a tendon sheath. Could also be a thrombosed vein based on your description you should seek out an examination

Hand Lumps and Bumps: are of many varieties but teh most common is a ganglion which is a benign not harmful fluid filled sac. Blusih color may indicate vascualrity, either there are veins over this or there could be a thrombosed vein or a varicosity. Sometime though skin lesions and skin cancers can look bluish as can some infactions or growths. If it is painful or changing please get evaluated

Vascular: Usually, this coloration suggests a vascular mass. If it is painful, see a hand doctor. If you have had this for a long time and it is not painful, I would not be too concerned. A ganglion is a benign mass which does not have a color to it. If the mass is on the skin and not deep, see a dermatologist.