True (and increasingly rare) Herkimer Diamonds come only from one specific region near New York in the USA. Similar double terminated formations are found in other areas of the world, but only herkimers have the "true" Herkimer energy and clarity. Although a formation of clear quartz, they are slightly harder on the Mohs scale (7.5 rather than 7). This means that in general they have a very fine clarity: many will have rainbows. It is also possible to find pale grey/brown "smoky" herkimers: their colour being the result of disseminated anthraxolite (a coal-black mineral). Some may be slightly coloured yellow by iron or mineral oil materials (Judy Hall calls these citrine herkimers), and they exhibit other inclusions such as water, pyrite, dolomite or anthraxolite crystals within or on their surface. True Herkimer Diamond crystals are stubby and double terminated and tend to grow in branching clusters, which means that their surface may exhibit indentations, keys or natural damage where they have separated from their clusters or from groundmass during the extraction process. This natural damage does not affect their energies. The extraction process also may result in splitting or fracturing of the crystals - once again this does not affect their energies, but will mean that they might not be able to be used as you might a fully double terminated specimen.
From a metaphysical point of view Herkimers are one of the best holders and carriers of full spectrum Light and can powerfully recharge a depleted energy system AND are very efficient cleansers of negativity. They will also provide clarity in all thinking and reasoning processes.
FOR A DEFINITION OF THE GRADING SYSTEM WE USE, SEE "SMALLER SPECIMENS"