Magnifying glass icon font using Dashicons for Search button in Genesis. http://sridharkatakam.com/add-magnifying-glass-icon-font-using-dashicons-search-button-genesis/

functions.php

//* Enqueue Dashicons
add_action( 'wp_enqueue_scripts', 'enqueue_dashicons' );
function enqueue_dashicons() {

	wp_enqueue_style( 'dashicons' );

}

//* Customize search form input button text
add_filter( 'genesis_search_button_text', 'sk_search_button_text' );
function sk_search_button_text( $text ) {

	return esc_attr( '' );

}

gistfile1.php

//* Customize search form input box text
add_filter( 'genesis_search_text', 'sp_search_text' );
function sp_search_text( $text ) {
	return esc_attr( 'Search' );
}

style.css

input:focus::-webkit-input-placeholder { color:transparent; }
input:focus:-moz-placeholder { color:transparent; } /* Firefox 18- */
input:focus::-moz-placeholder { color:transparent; } /* Firefox 19+ */
input:focus:-ms-input-placeholder { color:transparent; } /* oldIE ;) */

.search-form {
	position: relative;
}

.search-form input[type="submit"] {
	position: absolute;
	display: inline-block;
	-webkit-font-smoothing: antialiased;
	font: normal 20px/1 'dashicons';
	vertical-align: top;
	clip: inherit;
	width: 20px;
	height: 20px;
	background: transparent;
	color: #999;
	right: 10px;
	top: 17px;
}

.search-form input[type="submit"]:hover {
	color: #F15123;
}

.site-header .search-form {
	width: 189px;
}