10 most difficult minerals riddlesMinerals quiz
What's the origin of the word "turquoise"?
Turku City in Finland
Turkey as a country
Turkusy, fake region
The name Turquoise was established in the seventeenth century and came from the name of Turkey (turquoise is French for "Turkish"), because the mineral was first brought to Europe from Turkey. Ancient Romans called this rock Kalalit.
Which of these elements is not a "rare earth metal"?
Despite their name, rare-earth elements are – with the exception of the radioactive promethium – relatively plentiful in Earth's crust, with cerium being the 25th most abundant element at 68 parts per million, or as abundant as copper. They find application in the most dynamically developing areas of high technology industry such as: aviation, space flights, production of mobile phones (smartphones).
Which of the following is not an allotropic variety of coal?
An allotropy is a phenomenon of appearing, in the same state of aggregation, of all sorts varieties of the same chemical element, differing in physical properties and chemical. Coal is appearing mainly in the form of diamond, graphite, fullerene and graphene. Anthracite is simply a variety of the hard bituminous coal.
Sapphire is a blue variety:
Sapphire is a gemstone, a variety of the mineral corundum, an aluminium. It is typically blue in color, but natural "fancy" sapphires also occur in yellow, purple, orange, and green colors. Pink colored corundum may be either classified as ruby or sapphire depending on locale.
Which of the minerals below show pleochroism?
Pleochroism is an optical phenomenon in which a substance has different colors when observed at different angles, especially with polarized light. Alexandrite appears greenish in daylight where the full spectrum of visible light is present, and reddish in incandescent light which emits less green and blue spectrum.