gazebo material not working

edit

when i use the code:

  <gazebo reference="link_1">
    <material>Gazebo/OrangeTransparent</material>
  </gazebo>

it shows the color of the link. but when i use below code it doesn't:

  <gazebo reference="link_1">
    <material>
  <ambient>1 0.5088 0.0468 1</ambient>
  <diffuse>0.46 0.46 0.46 1.0</diffuse>
  <specular>0.5 0.5 0.5 128</specular>
  <emissive>0.46 0.46 0.46 1.0</emissive>
</material>
  </gazebo>

i'm using gazebo 9, ros kinetic. and i'm using stl mesh.