Cal and Leonard have been joint venturing since Cal left Pala Properties International and joined Leonard in his Minerals America booth at a California Federation show in Anaheim in the 1970s. They later began doing shows as Graeber & Himes from coast to coast, providing high quality mineral specimens and rarities.

Both Cal and Leonard have professional degrees relating to minerals. In addition to attending the major shows in the US, they both have home showrooms where they meet clients by appointment. They also maintain busy labs for specimen preparation and have years of experience as mineral appraisers.

Both are veteran filed collectors. Cal is a partner in UK Mining Ventures, providing the world with superb green fluorite from England. Leonard has produced specimens for retail from Florida to California and handles top specimens from Mt Mica, Maine for the mine.