Benitoite
Much has changed since the rare mineral stopped being listed as part of GemGuide pricing eight years ago.
Gem NotesPhosphophyllite
The mineral is rare and, because of the value of well-formed specimens combined with a low hardness, brittleness, and cleavage, seldom seen faceted.
Gem NotesSphalerite
Though its best-known source was the Aliva Mine in Spain, the mineral has been sourced in a handful of other places. But it isn’t often seen in jewelry due to a few specific characteristics.
Gem NotesMontana Sapphire
The latest Gem Note dives into the differences in sapphires sourced in Montana and why it’s so hard to price Rock Creek and Missouri River corundum.
Gem NotesCassiterite
It’s a common mineral, found on every continent, but faceting rough is rare—unfortunate, since its lighter versions can display dispersion almost twice that of diamond.
Gem NotesTrapiche Emerald
Trapiche emeralds are far from common and generally not available “off the shelf;” availability is sporadic at best.
Gem NotesPezzottaite
Named after Dr. Federico Pezzotta from the Natural History Museum of Milan for his work on Madagascar’s granitic pegmatites, this rare mineral species is relatively new.
Gem Notes