BLUE tourmaline is very, very rare for San Diego County and this is a special piece with special quality, collected by an amazing person in fall of 1955 (see below). It was collected by the great author and collector John Sinkankas, who helped build up Southern California as the center of mineral collecting in the mid 1900s. This is a translucent to slightly gemmy green-blue Elbaite Tourmaline crystal. The crystal is rather tall, wide and thin which increases its translucency/transparency relative to volume and for this particular pocket, makes it a very special thing indeed, as it displays with much more color than the few others we have seen and had over the years. The top half of the crystal is considerably more gemmy, and the bottom half is much more translucent on the other side of the natural "tectonic bend" showing the stressful environment of crystal formation in San Diego at the time (up to 10 km below ground and under heat and pressure!). The top termination is flat, slightly etched is very dark blue for the top 0.5 mm at the cap. The prism faces are strongly striated parallel to its length and there are at least two stages of tectonic bending evident from the rehealed fractures and the change in direction of the striations in the bottom third of the crystal. There is also a complexly formed, 1.4 cm Quartz crystal near the top of the piece. A fine and rare San Diego indicolite, which is rare in such size and condition anyhow, but the HISTORY here is so neat! We have a label of John's from one of his published specimens we had back in 1999 or so, shown here, which confirms he collected these in the fall of 1955: https://www.irocks.com/minerals/specimen/2769. This is, pedigree aside, a very FINE indicolite for San Diego which has only rarely produced pure end-member indicolites of any quality. Examples from this pocket are documented in only a few major collections over the years, including John Barlow, Bill Larson, Chuck Houser and Irv Brown, and Klaus Neumann's suites of County material. It is the kind of thing that only turns up as the last of the old SoCal guard collections turns over, and Rock's might now be, sadly, the last intact from that era. Although no label survives, it is assumed this came from Sinkankas in his many trades and exchanges. John lived in San Diego, Rock in LA. They were near, and traded frequently with one another for decades.