My understanding is that IBM-Graph uses Titan, backed by Cassandra as it's persistent datastore.
In this stack it is usual to have a separate, search-index of Solr, Lucene or Elasticsearch, in order to enable more advanced queries like full-text search and geo-related queries.
Does IBM-Graph implement a search index such as this? If so, which one. And also, are these more advanced queries exposed via 'gremlin', i.e can we make use of this search index manually in order to perform full-text queries?