It sounds like you're describing various types of prisms made from English glass with polished surfaces. Here's a breakdown

Transparent & Clear Prism: This is a general term for a prism made from clear glass, allowing light to pass through it and creating spectral colors when dispersed.
Equilateral Prism: This prism has three equal sides and three equal angles, typically 60 degrees each. It's often used for dispersion of light into its constituent colors.
Right Angle 90°x45°x45° Prism: This prism has one right angle (90 degrees) and two angles of 45 degrees each. It's commonly used for redirecting light at a right angle.