Android LinearLayout change color of separated line

Question

I have horizontal orientation in LinearLayout and my items in the list separated by default with bottom grey line.

is it possible to change the color of this separated line ? if yes how it will look like ?

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/resizeablecontacts"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/mainBackground"
    android:layout_margin="10dp"
    android:orientation="horizontal"
    android:weightSum="3">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_marginTop="5dp"
        android:layout_marginBottom="5dp"
        android:orientation="horizontal"
        android:weightSum="3">

        <de.hdodenhof.circleimageview.CircleImageView
            android:id="@+id/userthumb"
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_weight="0.5" />

        <RelativeLayout
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_weight="2"
            android:weightSum="4">

            <TextView
                android:id="@+id/username"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:layout_weight="4"
                android:gravity="left|center_vertical"
                android:paddingLeft="10dp"
                android:text=""
                android:textColor="@color/textFieldText" />
    </LinearLayout>
</RelativeLayout>

The items in the list are CircleImageView and TextView.