Opaque particles do not contain transparency

I’m trying to create a group of opaque, black particles. I have a .PNG I am using which contains a black image against a transparent alpha background.

However, when I try to create opaque particles in Unity (using the Particles / Standard Unlit shader), all I can seem to get are these black boxes.

When I change particle emission color, I notice that i can see the desired shape inside the black box, in the specified color, leading me to believe that the alpha channel is simply being interpreted as black.

I have double checked to make sure that the texture’s “Alpha Is Transparent” box is checked.

Thank you in advance for the help!

Opaque and transparent are complete opposites, therefore you cannot have an opaque material with transparency; it just doesn’t really make much sense. All particles are rendered as quads, as such if you set the render mode to opaque, the whole quad will be drawn with whatever texture you have set as the colour. If you wish to have transparency, you’ll need to change the rendering mode (‘Fade’ for traditional alpha blending, ‘Cutout’ for opaque with a set outline, ‘Transparent’ for pre-multiplied transparency, etc).