static public function mosaicQuantityToXEM($divisibility, $supply, $quantity, $multiplier = Amount::XEM)
    {
        if ((int) $supply <= 0) return 0;
        if ((int) $divisibility <= 0) $divisibility = 0;

        return self::XEM_SUPPLY * $quantity * $multiplier / $supply / pow(10, $divisibility + 6);
    }