Linear A is what archaeologists have called the as-yet-undeciphered written language (or script) of the Minoan people. It is one of two used during the Proto-palatial period (1900-1700 BC): Linear A was used in the central-southern region (Mesara) of Crete; and Cretan hieroglyphic was used on the northern and northeastern parts of Crete. Some scholars see these as simultaneous scripts, others see Cretan hieroglyphics as having been developed slightly earlier.
Invented about 1800 BC, Linear A is Europe's first known syllabary--that is to say, it was a writing system using different symbols to represent syllables rather than pictograms for complete ideas. It includes about 100 different symbols, and was apparently used for both religious and administrative functions. The scripts are found on a broad range of items, including inscriptions on stone, metal and ceramic vessels; stamp seals and roundels (and their impressions on tokens and bullae) used by Cretan administrative persons; as well as part of inscriptions which were painted and carved into tombs and altars.
Some researchers have argued that some--but by no means all--of the characters on the still-controversial Phaistos Disk resemble Linear A script signs.
Linear A and Saffron
A 2011 study into possible signs in Linear A that might represent the spice saffron was reported in the Oxford Journal of Archaeology. Archaeologist Jo Day points out that although Linear A has yet to be deciphered, there are recognized ideograms in Linear A that approximate the Linear B ideograms, especially for agricultural commodities such as figs, wine, olives, humans and some livestock. The Linear B form for saffron is called CROC (the Latin name for saffron is Crocus sativus): during his attempts to crack the Linear A code, Arthur Evans thought he saw some similarities to CROC, but reported no specifics and none is listed in any of the other previous attempts to decipher Linear A (Olivier and Godart or Palmer).
Day believes a plausible candidate for a Linear A version of CROC might be one sign with four variants, A508, A509, A510 and A511, which is found primarily at Ayia Triadha, with examples at Khania and the Villa at Knossos. These are dated to the Late Minoan IB period and appear in lists of goods: previously researcher Ilsa Schoep suggested the sign referred to another agricultural commodity, perhaps a herb or spice such as coriander. While the Linear B CROC symbol does not much resemble A511 or the other variants in Linear A, Day points out similarities of A511 to the configuration of the crocus flower itself. She suggests that the Linear B sign for saffron may have been a deliberate adaptation of the crocus motif from other media, and it may have replaced the older symbol when the Minoans began using the spice.
Linear A and Cretan Hieroglyphic
Both Linear A and Cretan Hieroglyphic were used on sealings, leading researcher Schoep to believe that they reflect a fairly sophisticated administrative system in place on Crete as early as the pre-Palatial period (~1900 BC). Linear A scripts have been found in quantity at the Minoan sites of Ayia Triadha, Khania, Knossos, Phaistos, and Malia.
About 1450 BC, Linear A disappeared, replaced by the language called Linear B. Linear B has been deciphered, and was found to be a form of archaic Greek.
Scholars are divided, to say the least, about the origins, possible language and disappearance of Linear A. Some say the disappearance results from invading Mycenaeans who crushed the Cretan culture; others such as John Bennett suggest the Linear A script was retooled to include additional signs to record a new language. Certainly, Linear B has more symbols, is more systematic and exhibits a "tidier" appearance (Schoep's term) than Linear A: Schoep interprets this as reflecting the ad hoc nature of reports written in Linear A versus a more regulated archival purpose for those in Linear B.
The best online source on Linear A (if a bit technical) is from John Younger, whose page on the Haghia Triada site contains many (if not all) the corpus on Linear A.
Day J. 2011. Counting threads. Saffron in Aegean Bronze Age writing and society. Oxford Journal Of Archaeology 30(4):369-391.
Eisenberg JM. 2008. The Phaistos Disk: One Hundred Year Old Hoax? Minerva 19:9-24.
Lawler A. 2004. The Slow Deaths of Writing. Science 305(5680):30-33.
Schoep I. 1999. The origins of writing and administration on Crete. Oxford Journal of Archaeology 18(3):265-290.
Schoep I. 1999. Tablets and Territories? Reconstructing Late Minoan IB Political Geography through Undeciphered Documents. American Journal of Archaeology 103(2):201-221.
Whittaker H. 2005. Social and Symbolic Aspects of Minoan Writing. European Journal of Archaeology 8(1):29–41.