Land Down Under Trivia Quiz

Answer: Amethyst

Amethyst is a type of quartz that contains slight impurities in the form of iron which give it a violet to purple colour. It is commonly found inside geodes - a type of hollow rock or cavity in which dissolved minerals enter and continue to grow hardening the outer covering. Amethysts were highly valued until the 18th century when extensive deposits of the mineral were discovered in Brazil leading to a sharp decline in its rarity and consequently, its price.

The other three incorrect options are also varieties of quartz. Citrine is usually yellow, prasiolite is green and onyx is a banded form of quartz.

Answer: Star

The trapiche emeralds are a rare type that are found only in three mines in Colombia - Muzo, Peņas Blancas and Coscuez, all three of which are located along the Carera river. The stones contain carbon impurities that radiate outwards from a central core forming a six pointed star. Other regions famous for emeralds include Pakistan, Zimbabwe and Russia.

Another gemstone from the beryl family is the aquamarine which is a blue variety of beryl. The blue colour is due to the presence of iron in the stone.

Answer: Olivine

Olivine is a magnesium iron silicate with two main varieties - forsterite which has a greater percentage of magnesium and fayalite which contains more of iron. Peridot is a forsterite olivine that occurs in only one colour - green. While olivine is found abundantly, the gem variety of peridot is rare and is found almost exclusively in basic igneous rocks that are high in magnesium and iron but low in silica.

While the Arizona reservation is one of the largest sources of peridot, the variety found in Myanmar and Egypt is considered to be of superior quality.

Answer: Christmas Obsidian

While obsidian is generally black, varieties of red, green, brown and grey also exist. The rock is commonly found in lava flows in locations ranging from the United States to Mexico and Italy. Apache Tears are small, round nuggets of obsidian which were made smooth by the actions of either wind or water.

The presence of small air bubbles in the rock forms Rainbow Obsidian which has a rainbow like sheen or Sheen Obsidian which has a golden sheen. If inclusions of cristobalite, a form of silica, are present in the rock, they form a snowflake like pattern known as Snowflake Obsidian.

Answer: Blue

Larimar is a rare variety of the mineral pectolite and is found only in the Dominican Republic where it was officially discovered as recently as 1974. The blue colour is a result of the presence of copper in the stone. The blue colour of the stone is photosensitive and fades with continued exposure to light and heat. Various nicknames for the stone include 'Atlantis Stone' and 'Dolphin Stone'.

Answer: Tanzanite

Zoisite is a silicate mineral commonly found in metamorphic rocks. The zoisite mined in Tanzania is a rare blue-purple variety unique to the region. The gemstone was named Tanzanite by a jewellery company Tiffany & Co. which attempted to cash in on its rarity.

The mineral is a reddish brown colour when mined and the blue purple hue of the stone is brought out by artificially heating it. Tanzanite is famous for its trichroism - when viewed under polarized light, it shows different colours in different directions depending on the internal orientation of the crystals.

Answer: Lapis lazuli

Lapis lazuli, known for its deep blue colour, is largely made up of the mineral lazurite. The rock is formed from limestone by the process of metamorphism. Lapis lazuli was widely favoured by ancient civilizations ranging from the Egyptians to the Sumerians and Assyrians among others.

Answer: Corundum

Corundum is the second hardest mineral after diamond and the gem variety is most commonly mined from gem gravel beds. This method of mining is relatively easy and involves using a screen to separate the dirt and gravel from the gems with the help of water.

While sapphires are generally associated with the colour blue, all varieties of corundum are called sapphires expect the red coloured ones which are called rubies.

Answer: Jade

Jade has been closely associated with China since ancient times. However, majority of China's jade has been obtained from the mines of neighbouring Myanmar. The toughness of the stone resulted in it being used in the manufacture of weapons and tools. Jade is derived from two different metamorphic rocks - jadeite and nephrite which, while largely similar have slight differences in their chemical composition.

Answer: No

The opal is classified as a mineraloid due to its non-crystalline structure. Australia is the world's largest source of opals with over 90% of the world's production mined here. The opal is also designated as the national gemstone of Australia. There are various types of opals with the most valuable being the black opal due to its rarity.