The BitMEX .ETCXBT Index tracks the Eth. Classic price every minute. The Eth. Classic price is calculated from the last price at Poloniex. The .ETCXBT index price is shown on many pages as the current Eth. Classic price.
This index is composite, which means the price is built from multiple sources. See the "Composite Index Breakdown" below for information on the constituents. If an exchange is to lose service and no trades are printed for over 15 minutes, BitMEX services may automatically remove that constituent from the index until trading resumes.