retrieve data from the uri.
Examples
if (FALSE) {
library(httr)
uri <- "https://api.mindat.org/geomaterials/?id__in=&hardness_min=9.3&fields=name,+
hardness&page_size=1500"
mindat_cache_set('api_token',"9ce67655d74bcd981e937be80dcea9cb")
df <- mindat_get_data_from_uri(uri)
}