25. Between a rock and a hard place: Hydrated potassium sodium iron magnesium aluminum silicate is better known as what?
From Quiz Omigosh, it's the "O" Quiz!
Answer:
Osumilite
Osumilite is a silicate, found in Japan, Northern Ireland, South Africa, Italy, Germany and in Oregon, USA. With a hardness of 5-6 on the Moh's scale, it ranges in colour from pale blue or gray to pink, brown and black. It has no real use except as a rock in a mineral collection.
Oligoclase, sodium calcium aluminum silicate, is a silicate of the feldspar group, sometimes called either sunstone or moonstone. It is usually milky white but can range into pale green or brown. It has a hardness of 6-6.5 on the Mohs scale, and can be found in Sri Lanka, Canada, Russia, Sweden and New York, USA. It is sometimes used as a semi-precious stone in jewelry.
Orpiment is arsenic sulfide, soft at 1.5-2 on the Moh's scale, and normally found with the mineral realgar. Its golden yellow colour is fairly distinctive, but cannot readily be used in dyes as the mineral is instable and will over time deteriorate to a powder when exposed to light. It also has a sulfury smell from the arsenic. It is found in Peru, Romania, Japan, Australia, and in Utah, USA.
Otavite is cadmium carbonate; it is found mainly in Namibia, although it has also been found in Australia and New Mexico, USA. It has a hardness on the Moh's scale of 3.5-4, is usually white but can also be brownish, and effervesces in acid.