Chrysoberyl

Chrysoberyl is a hard gem mineral, a beryllium aluminate (BeAl2O4) that scores 8.5 for hardness on the Mohs scale. Its name joins the Greek words for gold and for beryl, yet Wikipedia stresses that it is an entirely separate mineral from beryl, though the two share beryllium, aluminium and oxygen; Hall, for her part, files it under beryl. The common stone is a yellowish green that ranges from clear to translucent, and its tabular or stubby prismatic crystals often twin in threes into hexagonal-looking trillings. It forms in pegmatites and in neighbouring rocks such as mica schist and dolomitic marble, and since it shrugs off weathering it gathers in river gravels, the source of much Brazilian and Sri Lankan stone. Wikipedia names three main kinds: the plain yellow to green stone, cat's eye (cymophane) and colour-changing alexandrite. Hall ties chrysoberyl to new beginnings, to compassion, forgiveness, generosity, confidence and creativity, and says it lets a person weigh the two sides of a question and plan ahead. She also associates it with self-healing when it is used alongside other crystals.