All Caithness Limited edition's are marked on the base Caithness Scotland together with the name of the paperweight and the edition number. If the base is to small to take the Caithness stamp, or if the clear nature of the base would make a stamp undesirable aesthetically, the information was inscribed by hand using an engraving tool.

In 1983 a system of numbering was introduced for the unlimited production paperweights, consisting of a letter to denote the year starting with a letter to denote the year starting with A in 1983, followed by the number of unlimited paperweights produced so far that year. IE: if the weight has the number D158 that would make it a 1986 weight and would be the 158 weight of that style.

In 2006 Caithness Glass went into receivership and was put in the hands of receivers "Deloitte & Touche" who sold off the Caithness museum peices, alot of these very rare one off paperweights where unmarked as they where made for the museum. These unmarked paperweights where sold off with letters of authentication.

The limited Ed weights that where sold of from Caithness museum where sold with there original or duplicate certifcate. Most of these weights and perfume bottles are number one of that edition type. If you are luckly and get your hands on any of these very rare museum peices they are sure to become the jewel of any collection.

Dartington Crystal (torrington) LTD has acquired Caithness Glass from the receivers and Caithness Glass is back in operation from it's Inveralmond site at Perth in Scotland. I have been told that January 2008 Caithness glass moved to there new home in Crieff Scotland.

One more thing to note about the marks on the bottom of Caithness paperweights. The company did sell "second" quality paperweights through it's visitor centre showrooms they are always marked on the base with one of the following marks CIIG, C2G, CG2 CGII or just II.

I have been informed that the Caithness paperweights with the sticker "unselected" on the base are seconds. 

Thankyou for taking the time to read my Guide, hope it helps you build your collection.