All Herkimer Diamond crystals have metaphysical properties. According to Melody, author of "Love is in the Earth", Herkimer's are the attunement stone and vibrate to the number 3. These gemstones have a wonderful feel. Sizes & descriptions:

• Character, shape and clarity define this 20x17.5 mm crystal. It has a pyramid shaped facet and another facet sports a four sided key mark. The Herkimer has an over pyramid look. A frosty growth occurrence gives the crystal an unusual look from certain angles. A very charismatic crystal that comes through in the pictures below.
• Electric rainbows shine from many of the touchable and complete facets on this Herkimer Diamond. It measures 28x21x14 mm and has one strong complete termination point. The other end is a conglomeration of key marks. If your looking for a metaphysical crystal with rainbows, you may be drawn to this gemstone. The pictures do not do it justice. The very pale yellow iron deposits on the crystal reflected much darker in the pictures above than they actually are.

Both crystals are very touchable, making them great candidates for metaphysical work.
You may be interested to know the energy of these Herkimer crystals is quite pure, as myself and my husband are the only ones to have held it in the 300 million years since it was created (yes, that's 300,000,000 years)!