名稱   冰洲石	Name   Iceland Spar
化學公式   CaCO3	Chemical Formula   CaCO3
莫氏硬度   3	Mohs scale of Hardness   3
描述   冰島晶石是一種透明，無色的方解石結晶品種。它出現在容易分裂的大晶體中，容易被菱形分割，並且以其雙折射而著稱。	Description   Iceland spar is a clear, transparent, colorless crystallized variety of calcite. It occurs in large readily cleavable crystals, is easily divisible into rhombuses, and is remarkable for its birefringence.
小挑戰 冰晶石有什麼用？ 它具有許多用途，從精密光學儀器到LCD屏幕，甚至在第二次世界大戰期間用於製造瞄準鏡	Challenge What is the use of ice spar? It has many uses, in everything from precision optical instruments to LCD screens, and was even used during WWII to make bombsights

Reference

https://stonebridgeimports.com/a/386-what-on-earth-is-iceland-spar

http://www.visiteskifjordur.is/icelandic-spar/iceland-spar-vikings-use-navigation/

https://en.wikipedia.org/wiki/Iceland_spar

by Lau Ka Him on 19 April 2021