🔹 Small blue diamond UTF-8 character with hex code 1F539

Using HEX code of Small blue diamond in HTML file

<span> &#x1F539; </span>

Using Decimal code of Small blue diamond in HTML file

<span> &#128313; </span>

Using HEX code of Small blue diamond in CSS file for content

span { 
    content: '\1f539';
}