Choose the shown instrument and draw an ellipse, like it is demonstrated below.

Copy this layer and apply the white color on it. Place it under the main one. Displace it a little bit.

Insert one more ellipse with the color 304899.

And one more. The gradient’s parameters are indicated the next step.

The last element includes representing the highlight on the glass. Make an ellipse also with the color ACC8E0.

The final result!