The April birthstone is the diamond, the hardest known gem

The April birthstone is the diamond, the hardest known gem

The April birthstone is the diamond. And a diamond solitaire ring is a popular choice for engagement rings. Image via EarthSky’s Marcy Curran. The April birthstone The April birthstone is the diamond. It’s treasured for its exceptional hardness and purity of color. Although the diamond is not the rarest of gems, it’s still one of the most popular gemstones. As a result of a diamonds’ cold, sparkling fire, it’s held us spellbound for centuries. W…