21. Gabrielite is a sulfosalt mineral species occurring as idiomorphic crystals commonly found in cavities of a Triassic dolomitic rock. 22. Wolfe concluded that the material was anapaite partially altered to collinsite and he discredited messelite as a valid mineral species . 23. There are about 20 mineral species that qualify as gem minerals, which constitute about 35 of the most common gemstones. 24. Forming 12 % of the Earth's crust, quartz ( SiO 2 ) is the most abundant mineral species . 25. The goal is to promote the science of mineralogy and to standardize the nomenclature of the 4000 plus known mineral species . 26. In nature, cumulates usually form from 2 mineral species , although ranges from 1 to 4 mineral species are known. 27. In nature, cumulates usually form from 2 mineral species, although ranges from 1 to 4 mineral species are known. 28. A study published in 2011 presented evidence that barbertonite is a polytype of stichite and should be discredited as a mineral species . 29. In rocks, some mineral species and groups are much more abundant than others; these are termed the rock-forming minerals. 30. The now empty angular holes are interpreted as being cavities once filled by a highly soluble mineral species , most likely a magnesium sulfate.
