In 2020, for the first time in decades, a sudden  global epidemic crisis interrupted the author's annual travel schedule. It's as if the world has hit the pause  button, and the travel plans that have been interrupted by the outbreak seem like yesterday but are  felt like a lifetime away. It was also a rare experience  for Mr. Lucas that he could not go out for such a long  time to carry out field trips and write market reports.  Although the body has not moved, the heart has already gone far. During the epidemic period, the Field  Gemology Handbook, which the author spent one  year creating, is an elixir to all those who have the  heart to travel but cannot leave. Let's start an adventure journey of global treasure hunting together by  following his footsteps to trace the source of gems. Starting with "what is a field gemologist" and  explaining the concept of "mine to market" in a comprehensive way, the author has summarized his fieldwork over the past 30 years, recounting his personal  and valuable experiences. Mr. Lucas went to the legendary gem mining sites countless times, sharing his  knowledge and perspectives of gemology, interviews,  marketing, and the values of the supply chain. Ways  to conduct field expeditions and to buy at the source  are elaborated in the book, at the same time endowing the gem trade with romanticism.