Calcite in its natural state is a fairly soft stone (Mohs hardness of 3). This carbonate stone is found in nearly every color (including colorless). It may be white, gray, yellow, pink, green, blue, or purplish-red, and may have a vitreous or pearly luster. Most calcite beads are semi-translucent. It is difficult to facet due to its perfect rhombohedral structure, which gives it perfect cleavage in 3 directions. It is luminescent with fluorescent and UV light sources. Yellow calcite (often used for the solar plexus chakra, in chakra bracelets) is associated with self confidence and hope, and is believed to help dispel self-doubt and other energy blockages, and promote a new sense of optimism and motivation.
"Crazy Lace" Calcite is available in fantastic color options, for very nice prices. It is definitely a "reconstituted" or "block" type of gemstone, which means it is a mixture of resin, dyes, and potentially some gemstone content -- in this case, calcite crumbles left over (recycled) from other stone cutting projects. Our dyed "Crazy Lace" Calcite is durable and colorfast (it won't leak onto your customer's clothes, and the resin makes it much stronger than natural calcite), and we love the color selection.
Calsilica (or Imitation Calsilica) beads come in basic black & white, and sometimes brightly-colored, rainbow marbled patterns. Whether it's black & white, or the Rainbow Calsilica variety, it's a synthetic "gemstone" manufactured from a mixture of calcite, plastic/resin and artificial coloring pigments. Although some claim that calsilica is a naturally occurring material, there is little evidence to support this claim (the most persistent claim is that calsilica is mined in Chihuahua, Mexico). While some rainbow calsilica beads consist of powdered carbonate rock that is artificially colored and stabilized with plastic, most calsilica beads appear to consist of all manmade materials. This is why we refer to our stock as imitation (or faux) calsilica beads. However, they do look great, and they are the same calsilica "stone" that you'll find marketed elsewhere as a natural gemstone.