* SSEC -0.2 pct, CSI300 -0.2 pct, HSI -0.7 pct

* High aluminium prices lift Chalco profit, but shares off 5.1 pct

* Ping An gains on increase in H1 profit

SHANGHAI, Aug 18 (Reuters) - China stocks fell on Friday morning, as basic materials producers - which recently enjoyed major gains - are now getting hit by profit-taking, even when they have announced strong earnings.

The CSI300 index fell 0.2 percent, to 3,715.50 points at the end of the morning session. The Shanghai Composite Index also lost 0.2 percent, to 3,262.01 points.

China CSI300 stock index futures for August rose 0.1 percent, to 3,717.4, 1.90 points above the current value of the underlying index.

"The market is relatively stable and has made up ground after opening lower," said Zhang Qi, an analyst at Haitong Securities in Shanghai. "In general, A-shares have been relatively unaffected by external events like the terrorist attack in Spain."

Aluminum Corp of China Ltd (Chalco), among the most heavily traded components of the CSI300 index, fell 5.1 percent despite announcing that first-half net profit rose more than tenfold year-on-year, driven by high aluminium prices.

As of Thursday's close, Chalco A-shares shares had gained 56.4 percent since the beginning of July. Chalco shares in Hong Kong were up 37.5 percent over the same period, but fell 3.5 percent on Friday morning.

London aluminium prices on Thursday edged down from their highest levels in nearly three years as investors locked in profits.

The materials sub-index fell 1.5 percent.

Bucking weakness in the broader market, state-owned property developer and cement producer BBMG Corp jumped 4.9 percent after its subsidiary, Tangshan Jidong Cement Co Ltd said its net loss for the first half narrowed to 110.7 million yuan, from a 927.7 million yuan a year earlier.

Tangshan Jidong Cement shares rose 3.1 percent, and BBMG Corp's Hong Kong-listed shares gained 2.2 percent.

Ping An Insurance Group Co of China Ltd gained 2.7 percent in Shanghai and 1.4 percent in Hong Kong after announcing a 6.5 percent rise in first-half profit.

The Hang Seng index dropped 0.7 percent, to 27,149.69 points.

The Hong Kong China Enterprises Index lost 0.6 percent, to 10,731.78.

The index measuring price differences between dual-listed companies in Shanghai and Hong Kong stood at 128.59.

A value above 100 indicates Shanghai shares are pricing at a premium to shares in the same company trading in Hong Kong, and vice versa.

(Reporting by Andrew Galbraith; Editing by Richard Borsuk)