2023 Presenters Cal and Kerith Graeber

The Jewel Box Pocket Fluorite from Rogerley Mine, UK

Mining Fluorite at the Rogerley Mine, Weardale, County Durham, England
Cal and Kerith Graeber

Cal will speak firsthand about the trials and triumphs of mining in developed countries, and dealign with all the regulations and rules to get anything new out of the ground. His choice, England, was particularly interesting as the lands were owned by the Church and involvedĀ negotiations with both Church and State, as well as the locals.

He and his team, including his wife Kerith and friends Jesse Fisher and Joan Kureczka, found a way to mine safely and productively for more than a decade in these old mines. They will share stories and photos from those years.

The talk is dedicated to our mutual friend, Tim Sherburn, who passed away in 2023. Tim prepared the great majority of fine specimens from this mine for so many years.


Cal Graeber, is known widely as a traveling mineral dealer at major shows in the USA (always with wife Kerith). Recently, he finished a long ‘second career’ as a miner of the Rogerley mine for 19 years.Cal attended the Colorado School of mines and graduated with a degree in Geology and Mining Engineering in 1972. That same year Cal was hired by Bill Larson to help run the Pala Properties mineral dealership, and in 1980 he left to form his own business, Cal Graeber Fine Minerals.

Cal deals in fine mineral specimens, appraises collections, and provides professional cleaning and trimming services. Cal has traveled the world in search of specimens, and has been involved in various small mining projects, including operations in Tanzania for gem-grade spinel, and in Baja California for tourmaline; his current project (begun in 1999) involves mining for green fluorite at the Rogerley mine in Durham, England.

Cal’s wife, Kerith, was introduced to minerals by Bill Larson in the late 1960’s, where she later met Cal. They were married in 1978. Over the years she has built a very fine and much-admired personal collection of Mexican minerals.

Ex. Tim Sherburn Fluorite from Rogerley Mine, UK