Wiktionary
n. 1 One who collects sand samples as a hobby. 2 (context botany English) A plant that thrives in or requires a sandy environment to grow.
Wikipedia
An arenophile is one who collects sand samples, the interest of the hobby lying in the variety of texture, colour, mineralogy and location.
This hobby may include sand deposited on coastlines throughout the world. Some collectors may trade sands with fellow arenophiles.
Some collectors have included sand from rivers and mineral deposits if they meet the criteria according to diameter and physical properties, ensuring that the samples have met proper sand definition. (See Definition of Sand from the International Sand Collectors Society).
Only three places on earth have green sand; recently a supply has been found in Brazil. Papakolea Beach (also known as Green Sand Beach, Mahana Beach and, erroneously, Puʻu Mahana) is a green sand beach located at South Point, in the Kaʻu district of the island of Hawaiʻi. One of only two green sand beaches in the world, the other being in Guam,[1] the beach gets distinctive coloring from olivine crystals found in a nearby cinder cone. The rarest sands, from a collector's perspective, are found at Pitcairn's Island and Easter Island. Some sands, such as rare black and green sands in Hawaii, may not be collected due to their scarcity. The International Sand Collectors Society advises collectors become aware of any legal restrictions or permissions that may be required to collect sand from any public or and private location. The International Sand Collectors Society fosters contact for tips and sample swapping among collectors worldwide.