RAPAPORT... Gemfields has closed the majority of its business amid the coronavirus pandemic, and is unsure when it will hold its next tender."The turmoil stemming from COVID-19 [will have] a significant impact on [our] operations, revenues and business during 2020, and possibly beyond," the company said Monday.The miner has shut all but critical operations at its Kagem emerald mine in Zambia for at least a month, and believes it may need to do the same at its Montepuez ruby deposit in Mozambique. It has also halted exploration in Madagascar, while employees at its London and India offices are working remotely.The company is also considering postponing its tenders, depending on the health situation. Last year, approximately 93% of Gemfields' revenue was derived from its six gemstone auctions, it said."Due to the prevailing levels of uncertainty, Gemfields is unable to provide reliable guidance as to when it might be able to host its next auctions," the miner noted. "The emerald and ruby auctions originally scheduled for May and June 2020 are highly likely to be rescheduled for the second half of the year."Gemfields may also cancel its gemstone auctions scheduled for November and December should the market not adequately recover by then, it added.Image: Rubies from the Montepuez ruby mine. (Gemfields)