Recharging your Amber in the Sun
Leaving your amber in direct sunlight for extended periods of time is not only just a MYTH, it can actually can cause damage to your jewelry!
Researchers have found that the highest amount of succinic acid is actually found in the "cortex", which is the outer layer of the gemstone. Heating your amber would therefore NOT bring more succinic acid to the surface than is already there.
Avoid exposing your Amber Jewelery to Heat!
Experts advise AGAINST exposing your Amber jewelry to any heat, including the sun. Heat removes moisture from your amber gemstone, which makes it brittle. Amber can fracture with sudden changes in temperature. For example, being outside on a cold winter day and then coming inside and sitting by a warm fire could cause your beads to crack. Also, it is a good idea to remove your amber necklace before cooking.
Amber, like other gemstones, is actually sensitive to light and can darken over time. While this isn't necessarily a bad thing, you many really like your honey colored amber, and continued direct exposure for longer than casual periods to sunlight can make it darken.