You can tell it is a Record Keeper if it has an engraved or raised triangle-shaped symbol on one or more of its faces. The triangle shape is not limited to one, I have seen a record keeper with up to 10 triangles engraved on one side and they can often have little clusters of triangles on them. This is not an easy symbol to see most of the time, and you will have to examine the crystal closely in order to find a Record Keeper symbol if it is present. They do have a much stronger energy, so that is usually your first indication that there is something very special about the crystal.
Record Keepers are considered the most sacred of all crystal, this is due to the fact that it is believed that the ancient civilization of Atlantis programmed these crystals to hold all the knowledge of the Universe. This was done in order to record and safeguard the knowledge for all time before the fall of the Atlantis.
Record Keepers are also associated with Akashic Records and helping you to connect and have access to the infinite knowledge stored within the divine conciseness.
Akashic Records are a compendium of all human events, thoughts, words, emotions, and intent ever to have occurred in the past, present, or future. They are believed by theosophists to be encoded in a non-physical plane of existence known as the etheric plane.
If one is to use this Crystal to access the knowledge they would have to have an open mind and come into the endeavor with the purest of intents. If you wish to expand your being through meditation and knowledge and are ready for the journey then a record keep will find its way into your life in order to assist you to do this.
If you own one you are lucky, please treasure it.