I was first told about these fakes last year, single Calcite crystals glued together in clusters on basalt matrix.

FakeMinerals was given these pictures from Sami at Matrix India, exposing these fakes.

As you can see, the Calcites are grouped together in circular sprays. At the base of the crystals the glue is visible.

So, if you see any of these on EBAY or at a local rock show, beware, they are F-A-K-E!