Most seasoned Swarovski collectors know that Swarovski has two distinct logos.  The Swan is common to their highly collectible figurine line which contains animal, plant, insect and other whimsical shapes.  This logo is pictured below.

The Swarovski Strass logo is depicted by a trapezoid with a rainbow spectrum in the center with their name below and is associated with their prism line.  It is etched as a small trapezoid near the stringing hole.  This logo is pictured below.

In addition to the figurine line and prism line, Swarovski also manufactures pendants and beads which do not contain an etched logo.   These products are as genuine as their etched counterparts but due to the size of the object or Swarovski's marketing strategy they have chosen not to etch them.

Swarovski has recently made some startling changes to their prism line.    In Late 2006 they moved all the stars, moons, hearts, snowflakes and leaf prisms into their pendant line (6000 series).    In doing so Swarovski has removed the etched logo near the hole on all of these products as the pendant line does not carry any logo.    Swarovski has also discontinued, 50mm stars,  25mm snowflakes sizes and most of the colors and special effects in the current line.   The pricing in this new stock has increased dramatically, some up to 76%.    When the old stock is depleted you will see the stars, moons, hearts, snowflakes and leaf prisms without the logo.  This does not mean they are not genuine.   Many Swarovski prisms at this time do not carry the logo, such as the Spectra and Strass pendant lines.   Do not be concerned as it is hard to mistake a Swarovski prism.   Look for sharp crisp cuts and not molded, and the hole on Swarovski prisms have a sharp feel to them when you run your finger across the hole.  The superior shine, sparkle and refracting abilities are hard to mistake, especially when next to an inferior prism.