This beach on the Big Island boasts a one-of-a-kind color: olive green. The color of the sand is due to a type of lava crystal called olivine, which stays on the beaches because of its weight ...

Next time you’re at the beach, pick up a handful of sand and look closely at it. Are all the grains the same color, or a rainbow assortment? Are they jagged and angular, or smooth and round? The shape ...