Miriam “Mimo” Kamau Caplan and Evan Caplan

Miriam “Mimo” Kamau Caplan is a pioneering gemologist and gemstone dealer from Nairobi, Kenya. Born in 1975, she overcame early hardships, including the loss of her father, to support her family and forge an extraordinary career. Starting as a tea maker in a gem dealer’s office, her curiosity led her to study gemology at the Oppenheimer Institute in South Africa. She now holds certifications in diamond and colored gemstone identification and has excelled in cutting, sorting, and marketing gems for over 25 years. 

Miriam’s journey into gemstone mining, a field dominated by men and technology, is nothing short of remarkable. She braved harsh conditions, wildlife, and remote bush camps to mine gems herself. Today, she owns tsavorite mines in Kenya and leads with a focus on sustainability and community support, helping over 50 mining families. 

She is the Founder and Director of Mimo Gem Traders and Mining and Vice President of Evan Caplan Rare and Fine Gemstones. Miriam serves on boards, including the International Colored Gemstone Association (ICA), Women’s Jewelry Association (WJA) Los Angeles Chapter, and the Association for Women in Energy and Extractives in Kenya (AWEIK). Her awards and recognitions span the globe, including honors from Women in Mining UK and the Kenya Chamber of Mines. She is a tireless advocate for education, empowerment, and ethical mining practices. 

Evan Caplan is one of today’s foremost experts in colored gemstones, earning the nickname “the eye” for his exceptional sourcing ability. His journey began in the 1980s when a brief stint helping a friend in the colored stone trade sparked a lifelong passion. He pursued formal education at the Gemological Institute of America, earning a Graduate Gemologist^® diploma. 

Caplan’s background as a trained jazz musician from Berklee College of Music gave him a refined sensitivity that translated seamlessly into the gem world. His pursuit of rare stones led him to establish deep relationships in sourcing countries, including Burma, Brazil, Kenya, Tanzania, Sri Lanka, and more. He was among the first to introduce Paraíba tourmaline to the U.S. and played a key role in the cutting and sale of the world’s largest Padparadscha sapphire. 

Collectors and curators frequent his Los Angeles office, drawn by his discerning eye and rare finds. Fascinated by alexandrite—a rare, color-changing gemstone—Caplan is now regarded as an authority on the gem, lecturing globally. 

Today, he spends significant time in Africa, sourcing stones and working on mining initiatives aimed at improving local lives. Caplan has served on the boards of AGTA and ICA, continuing to shape the global gemstone trade.