Groutite is an uncommon manganese oxide, rare in sharp crystals and really known from just a few locales in good form. You can really see here the superb elongated crystals of groutite, to 6 or 7 mm, tucked safely into crags of quartz-replaced petrified wood! I have seen just 3 specimens of this material before, and in every case it sold immediately - this is rare, hard to obtain material. Courtesy of Carol Frey: This specimen is from a remarkable and so far unique find in 1975. A miner who'd worked in the area for years brought in a small lot of a dozen specimens to a rock shop owned by Lolette Dalbec in Ridgecrest, California in the 1980s. Apparently all the known specimens are from this find. Here we have a A CHOICE specimen with a vug filled with sparkly groutite needles on petrified wood from Arizona. from the Lewadny Collection. 3.6 x 3.1 x 1.7 cm