A "shell button" is a distinctive type of button that can be characterized by the following features:

1. ‌Natural Origin‌: Crafted from the shells of various marine organisms, such as seashells or mother-of-pearl, it offers a unique connection to the ocean and nature.

2. ‌Elegant Appearance‌: The button's surface often displays the intricate patterns and iridescent colors of the shell, adding a touch of elegance and sophistication to any garment or accessory.

3. ‌Delicate Texture‌: The natural texture of the shell, with its smooth curves and subtle ridges, provides a tactile experience that is both visually appealing and pleasant to touch.

4. ‌Durability‌: Despite their delicate appearance, shell buttons are surprisingly durable and can withstand the rigors of daily wear, making them suitable for a variety of applications.

5. ‌Eco-Friendly‌: Using shells, which are often byproducts of the seafood industry, reduces waste and promotes sustainability in fashion and accessories.

6. ‌Versatile Design‌: Shell buttons come in a wide range of shapes, sizes, and colors, allowing for endless design possibilities and making them suitable for both casual and formal attire.

7. ‌Timeless Appeal‌: The classic and refined look of shell buttons makes them a timeless choice that complements a variety of styles and trends.

8. ‌Cultural Significance‌: In many cultures, shells hold symbolic meaning and are associated with the ocean, protection, and fertility, adding a layer of cultural depth to the button.

In summary, a shell button is distinguished by its natural origin, elegant appearance, delicate texture, durability, eco-friendliness, versatile design, timeless appeal, and cultural significance.