VCLM jewelry is vintage pieces of costume jewelry with a specific marking of "VCLM." They are created by the vintage jewelry company VCLM.
Nordstrom
It is the makers name.
Jewelry should be collected because you love the piece not necessarily with the hope that it will improve in value. All the VCLM jewelry I have seen has been lovely and apparently good quality for fashion pieces. Most are also signed, one of the indicators of collectible pieces from a collector's perspective.