Deep copy of array of objects

Question

I made a class:

class configurations
{
    public double lowColumn1 = -1;
    public double highColumn1 = -1;
    public double lowColumn2 = -1;
    public double highColumn2 = -1;
    public double lowColumn3 = -1;
    public double highColumn3 = -1;
}

I want to make an array (con1), and make a copy of it (con2). I would like to change con2 so it will not change con1.

I think it is called deep copy, is it?

It is important that the copy will not consume a lot of running time, efficiency is important.

I tried .Clone() function which didn't help me.

Please tell me what is the most efficient way to adjust my code.

private void button8_Click(object sender, EventArgs e)
{
    configurations[] con1 = new configurations[3];
    con1[0] = new configurations();
    con1[1] = new configurations();
    con1[2] = new configurations();
    configurations [] con2 = new configurations [3];
    con2 = (configurations[]) con1.Clone();
    con2[0].highColumn1 = 999;
}

please do not make this as a duplicate. my program is very heavy and in other topics they do not discuss time efficiency. in addition to this aspect. i am very new to programming, and i couldn't made adjustments from other answers of other questions.