Diamond shapes with larger surface areas tend to appear bigger to the eye. The round brilliant cut is the most popular diamond shape and has excellent light performance, making it a popular choice for engagement rings and other jewelry. However, when it comes to looking the largest, there are other shapes that can visually outshine a round diamond of the same carat weight. Here are some diamond shapes that typically look larger:

1. Oval: The oval diamond shape elongates the finger and creates an illusion of a larger size due to its elongated appearance. It has a larger surface area compared to a round diamond of the same carat weight.
2. Pear: The pear-shaped diamond combines the brilliance of a round cut with the uniqueness of a marquise shape. The tapered point makes it appear larger than other shapes with similar carat weight.
3. Marquise: The marquise diamond is an elongated shape with pointed ends, which makes it visually stand out and appear larger than its actual carat weight.
4. Emerald: The emerald-cut diamond has a large table (the flat top surface), which allows more of the diamond's area to be visible. Though it may not have as much sparkle as a round brilliant, its large, open face makes it appear bigger.
5. Cushion: The cushion-cut diamond has a square or rectangular shape with rounded corners. It has a larger surface area and can create a vintage and romantic appeal.

It's important to note that while these shapes may appear larger, the perception of size can vary depending on the individual's preferences and the overall proportions of the diamond. Additionally, each shape has its unique appeal and charm, so it's essential to choose a shape that aligns with your personal taste and style. When selecting a diamond, focus on finding a balance between the appearance of size and the qualities that matter most to you, such as cut, color, clarity, and overall brilliance.